In stock form, the BMW M3 is one of the world’s best performance

cars. Available in coupe and sedan body styles, with real back seats

and useable trunks, the tangy Bimmers deliver 0-60 mph in the fives,

comfy room for four, and starting prices of $39,380. In all, a

masterful synergy of laser-sharp performance melded with

supple German luxury. Which leaves any sane person with

the questions: Who in his right mind would want to

modify one?

Plenty of folks, it appears. But it’s painfully clear

that, while anyone can bolt a bunch of go-fast parts on a

car and claim miraculous results, the tough part is making

it all work–and work reliably. For example, tweaking an

engine to monstrous power levels often means you’re

driving a hand-grenade-in waiting; likewise, installing girder-

size anti-roll bars, chopped springs, and race car bushings will

probably do equal damage to your sacroiliac as to your bank balance.

Quite simply: It’s easy to screw up a perfectly good stock car by the

wrong application of components.

So, how can you achieve higher performance without risking

damage to the superb balance and reliability of the factory M3?

That’s what we wanted to know.

Enter Dinan (Dept. MT, 150 S. Whisman, Mountainview, CA

9404; 415/962-9401), one of the world’s leading BMW tuning

firms. According to company founder and President Steve Dinan,

BMW North America thinks enough of Dinan’s products to allow

them to be sold in select BMW showrooms. What’s more, BMW

has just announced it will maintain its new-car warranty on

Dinan-modified vehicles in areas where the Dinan mods

could not affect the factory warranty; in response, Steve

Dinan has agreed to match BMW’s new-car warranty on

his company’s modifications. What this all means is

you get a fully warranted car regardless of the level of

modifications with Dinan parts.

But just how improves are Dinan’s creations? How

fast are they on the racetrack? How much do they punish

you on rough surfaces? How reliable are they in hot summer

stop-and-go traffic with the A/C cranked? Those are exactly the

questions Motor Trend set out to answer.

Steve Dinan brought us three levels of modified M3s, cars we’ll

refer to as Stage I, Stage II, and Stage III. We brought a stock M3

sedan along as a benchmark, and put it through the same tests on the

same day as the three Dinan cars. With a wide range of as-tested

prices and horsepower levels, we figured there’d be a lot to sort out,

and plenty of hairs to split. Turns out we were right. Read on.

STAGE I

It doesn’t seem to matter if the M3 in questions is a coup or sedan; both

body styles perform nigh identically, and respond in kind to Dinan’s

modifications. On this bright blue sedan, the only standout visual clues

of something new are the lightweight Dinan five-spoke wheels. But look

more closely and you’ll see a decidedly hunkered-down stance to the

font suspension that comes from lowering the car and dialing in 0.5 de-

gree of negative front camber. Bring to the party a set of Koni shocks,

adjustable anti-roll bars, and stress bars front and rear, plus hefty Michelin

Pilot SX 245/40ZR17 radials and you have the trappings of a bona fide

corner-burner.

On the highway: There’s a definite increase in tire slap over rough

surfaces above that of the stock M3 (which uses the same Michelin tires,

but sized 225/45ZR17 at the rear); however, the overall ride quality is not

compromised by much. An hour of 90-degree-day stop-and-go traffic

with the air conditioning on failed to elicit even a hint of crankiness from

the Dinan Stage I. The throatier exhaust note is completely in character

with the car, and is not at all obtrusive, but as with all M3s, this baby

needs a sixth gear from relaxed highway driving (engine speed at 60 mph

is a busy 2800 rpm).

On the handling course: Steering response feels quicker due to the

wider front meats, with virtually no understeer. In fact, it’s this cars’ rear

that becomes twitchy near the limit, limiting its prowess in the slalom to a

merely excellent 69.0-mph average speed.

At the drag strip: It’s above about 80 mph where the mild intake and

exhaust modifications begin to shine, producing a 0.3-second improve-

ment over stock in the 0-90mph dash. The quarter-mile time was an iden-

tical 14.2 seconds, but the resultant 1.2-mph increase in trap speed tells

the tale of extra high-end horsepower.

On the road course: Excellent steering feel and turn-in response.

However, the tires became overheated after just two laps, changing the

car into a tail-out drifter. Up until that time, however, the lateral grip was

truly centrifuge-like.

The verdict: A nice overall upgrade. Only a tick quicker than

the stock car in acceleration, but 1.2-mph faster through the slalom

and 0.07 g stickier on the skidpad. A very livable package in 99

percent of driving situations, but be aware this one may unnerve

novice drivers with its rearend twitchiness in extreme handing ma-

neuvers.

STAGE I

Philosophy: Simple engine modifications to slightly increase power;basic

suspension upgrades. Wheel and tire upgrades are optional.

This package is available at selected BMW dealers.

Engine mods: Air filter system, exhaust system

Horsepower: 257 @ 6000 rpm (17-horsepower gain over stock)

Torque, lb-ft: 245 @ 4000 rpm (9-pound-feet gain over stock)

Chassis mods: Koni shocks, coil springs (lower car

by 8 milimeters), adjustable front and rear anti-roll bars, front and

rear stress braces, negative camber plates at front (-0.5 degrees),

Dinan 17.0x8.5 inch 3-piece forged aluminum wheels,

Michelin Pilot SX 245/40ZR17 tires.

Dinan appearance items: Underhood plaque, engraved tailpipe tips,

decklid badge, floor mats

Basic package price, installed: $5370

Price of modifications as tested,

including optional wheel and tire package: $9450

STAGE II

For only $1650 more than our Stage I car, the purple Stage II Dinan-

equipped M3 coupe delivers some tasty additions in the engine bay.

The goodies include a high-flow throttle body, higher-lift intake and

exhaust camshafts, and a Dinan computer chip that alters the fuel enrich-

ment and ignition timing, as well as moves the rev limiter higher by a

couple hundred rpm. A high-performance clutch also is installed to help

deal with the powershifts that a Stage II owner will no doubt employ

while trouncing Mustang GTs and the like.

On the highway: Gawd, that sound! Rev’er above 5500 rpm and

those hot camshafts produce a Ferrari-like symphony of mechanized

music. Combined with its lusty exhaust note, this definitely isn’t a car for

stealthy high-speed motoring. One fast midnight run along Hollywood’s

twisty Mulholland Drive startled residents, upset the ecosystem, and

had every dog within a 5-mile radius barking for hours-what fun! Rude

quality improves over that of the Stage I car by virtue of this machine’s

slightly narrower tires, and makes for a livable commuter car that really

hauls the goods.

On the handling course: Added power has virtually no effect on our

slalom course or skidpad, because these tests measure chassis balance,

traction, and response. Therefore, it’s not so surprising that the Stage II

car turned in the same 0.93g rating on the skidpad as the larger-tire-

equipped Stage I, but that the purple M3 outran its blue sedan sibling by

a gigantic 3.1 mph I the slalom is startling. Either chalk one up to Toyo

tires, or there’s some other tuning trick in effect that Dinan isn’t talking

about.

At the dragstrip: With such an intoxicating Italianesque sound com-

ing from its engine, we expected the Stage II car to eat the Stage I for

lunch. Not so. Both posted identical 5.7-second 0-60-mph times, with

the more powerful M3 only opening up a slight lead by 90 mph. We ran

it, and ran it, and ran it again, but the Stage II wouldn’t go as fast as it

sounded.

On the road course: Compared to the outstandingly well-balanced

feel of the stock M3 sedan (certainly on of the most-capable-handling

four-doors the world has ever seen), the Stage II coupe cornered like it

was from another dimensions. It took four hot laps until the tires showed

any signs of going away, and continued to exhibit godlike balance and

control throughout its track testing. This one car we’d stand in line to

drive.

The verdict: With an engine sound to die for and enough

cornering grip to dislodge your internal organs, the Dinan Stage II

is like unlimited fun day at the autobahn amusement park. Now, if

it were just a little bit faster.

STAGE II

Philosophy: Create a more powerful, more aggressive M3

at an “attainable” price.

Engine mods: Stage I equipment plus:

high-flow throttle body, intake and exhaust comshafts,

modified computer software, high-perfomance clutch

Horsepower: 285 @ 6500 rpm (45-horsepower gain over stock)

Torque, lb-ft: 267 @ 4500 rpm

(31-pound-feet gain over stock)

Chassis mods: Stage I equipment plus:

Toyo Proxes RA1 235/45ZR17 Tires

Dinan appearance items: Same as Stage I

Basic package price, installed: $11,100
Price of modifications as tested: $11,100

Did someone say “faster?”

Faster is as faster does, and the Dinan Stage III gets there by virtue of

its supercharger. Adding 101 horses to the 3.0-liter DOHC inline six (this

particular car is a ’95 model, hence, the 3.0 liter, as opposed to the other

two newer M3s’ 3.2-liter sixes) gives you right-foot control over 341 horse-

power and 297 pound-feet of torque. This car doesn’t have the trick

camshafts of the Stage II, nor does it need them. The compact Powerdyne

centrifugal blower mounts on the left side of the engine block and looks

right at home in the pristine engine bay. Producing a mile 6 psi of boost,

the supercharger doesn’t give an initial shock of low-end torque as ex-

pected, but a smoother application of thrust that really comes on as road

speeds build. And because it’s so quiet, this the perfect stealth racer.

On the highway: This machine is ready to please in virtually every

situation. It’s 50-state emissions legal, and is as happy slogging through

urban traffic as it is tearing up the backroads at redline in every gear. Only

a slight underhood whine lets on that this M3 ain’t stock, which may give

an advantage in roadside interview situations. As with the other Dinan

Bimmers, ride quality is only considered harsh over really lousy surfaces,

although tar strips and concrete expansion joints are more intrusive than

in the stock car.

On the handling course: It’s to his car’s credit that it pulled 0.95g

skidpad orbit, a 71.7-moh slalom speed, and a 104-foot 60-0-mph stop

while shod with smaller-than-normal rubber. Dinan’s own specs car for a

255/40ZR17 tire front and rear, but none was to be found at the time of our

track test, so they substituted smaller 235s instead. However, we briefly

sampled the car on its worn-out 255s in street (and canyon) driving and

were completely astounded by the unholy levels of grip this car deliv-

ered. With unfettering control and balance over even rough-surface off-

camber turns and during hard braking on slippery ground, the Stage III

seemed to defy the laws of physics throughout our drive, and never

squealed a tire in the process.

On the dragstrip: The lowest launch rpm of our test quartet (3600

rpm) proved the most efficient for getting the supercharged M3 off the

line without too much wheelspin. The big power resides at 5000 fpm and

above, so not much other finesse was required to cook 0-600 mph in 5.0

seconds. Note the quarter-mile stats are a hefty 0.8 second quicker and

6.3 mph faster than stock.

On the road course: A challenging hilly racetrack like the 1.3-mile

Streets of Willow Springs is the perfect venue to test the sum of a car’s

components. Even wearing its smaller-than-designed tires, the Stage III

cornered and braked like a national champion, and had the extra power to

STAGE III

take full advantage of the fortified chassis (than the super aggressive

3.0-degree negative front camber settings for a good deal of that nimble

response). The tires lasted three timed laps before turning gooey, but

didn’t deteriorate the car’s fun factor one iota. Of course, the down-

side to that camber setting is rapidly wearing rubber, even in street

driving.

The verdict: If you have the bucks, this is the one to get.

STAGE III

Philosophy: An M3 for the ultra-high-performance driver.

Engine mods: Supercharger, exhaust system,

high-flow throttle body, modified computer software

Horsepower: 341 @ 6750 rpm (101-horsepower gain over stock)

Torque, lb-ft: 297 @ 5000 rpm (72-pound-feet gain over stock)

Chassis mods: Stage II equipment plus: negative camber plates at front

(-3.0 degrees), Toyo Proxes RA1 235/45ZR17 (see text)

Dinan appearance items: Same as Stage I
Basic package price, installed: $17,800

Price of modifications as tested: $17,800

DINAN M3 PERFORMANCE COMPARISON

Stock M3

Stage I

Stage II

Stage III

Acceleration
0-30 mph, sec: 2.0 2.0 1.8 1.7
0-60 mph, sec: 5.8 5.7 5.7 5.0

0-90 mph, sec: 12.4 12.1 11.9 10.3

Quarter mile, sec @ mph: 14.2@97.1 14.2@98.3 14.0@99.0 13.4@103.4
Braking 30-0 mph, ft: 29 30 27 26

Braking 60-0 mph, ft: 116 116 105 104
Handling, lateral acceleration, g: 0.86 0.93 0.93 0.95

Speed through 600-ft

slalom, mph: 67.8 69.0 72.1 71.7

Road course lap tim, min:sec.: 1:06.08 1:05.78 1:03.86 1:03.22