The 9.5x19- and 10x19-inch alloy wheels are Dinan's own. Spread forged for exceptional strength and lightness, at 19.8 pounds, they weigh about 4.4 pounds less than the same-size offerings from certain other respected manufacturers.Steve Dinan believes that road cars need decent spring travel and as near perfect as possible relationship with damper rates to work on public roads. This is why you will never see a Dinan car looking like an escaped DTM racer. "Not only do you limit spring travel by lowering a car too much, you will also run into problems with the larger rubber touching the wheel housings and suspension components when you are cornering hard and bottoming out on bumps," Dinan explains.
Although Dinan's springs are stiffer than the factory ones, matching to the specially valved JRZ dampers is well nigh perfect. These dampers are 12-point adjustable for bounce and rebound. While you would never describe the ride as being anything other than taut, the secondary ride is good enough to take the sting out of short, sharp bumps. On the sinuous and undulating hill roads near Dinan HQ, we found a measure of progression and control that goes beyond the factory suspension, and if anything, suspension performance seems to get better the harder you push the car.
All the suspension experts we have ever spoken to agree that anti-roll bars should only be used for fine-tuning. Dinan leaves the factory rear bar unchanged but swaps the front bar for a larger adjustable one. Normally a larger front bar promotes understeer, but this is mitigated by a combination of the wider front tires, the relationship between the new front and rear spring rates, softer low speed damper settings, and more negative camber with -1 degree front and -5 degrees rear. Dinan use camber plates on the front top shock mounts to achieve its settings and a strut brace to improve rigidity. A rear shock tower brace is optional for the really hardcore drive, although that admittedly eats into trunk space.
Dinan's big brake kit is made by Brembo and uses 14.9-inch and 13.6-inch slotted, vented floating discs with aluminum bells front and rear. The four-pot alloy calipers with Ferodo pads are plumbed in to the factory brake wear sensors. As you would expect, the brake pipes are Goodridge metal hoses.
All that extra power and torque would create a point-and-squirt scenario in many other cars, but with its upgraded chassis abilities, the Dinan M3 feels totally at home with its newfound power. In combination with the extra front-end bite, this setup enables effective deployment of the extra power and torque, and the M3 was devastatingly fast on the demanding hilly roads where we drove it.
That said, there is more than enough power to wag the tail at will now, so the best way to keep things neat and tidy is to moderate your entry speed, establish a neutral balance on constant throttle right up to the apex, and then steadily increase throttle, unwinding the wheel as you add power on your way out of the bend.
The resulting strong lunge for the horizon really gets into its stride once you are pointing down the straight with the throttle pedal buried in the carpet and the rapid build-up in speed is simply intoxicating.
As we trickled into Dinan's car park at the end of our hard run, we considered what the Dinan S3-R M3 represents. For $42,500 for a full spec conversion on top of the base car, you get a very comprehensively re-engineered M3 that bears comparison with much more expensive supercars and many of the best tuner cars we have tested over the years.
In Germany, a tuner this size and with Dinan's technical abilities would be able to apply for manufacturer status and thus be eligible to apply its own engine and chassis numbers to its cars. Dinan has been called America's answer to Alpina, and we'd have no hesitation in drinking to that.
*Layout
Longitudinal front engine, rear-wheel drive
*Engine
3.2-liter inline six, dohc, four valves per cylinder, supercharged and intercooledDinan S3-R supercharger package [Vortech supercharger, front-mount intercooler with integrated automatic fan, high-flow cold-air intake, high-capacity aluminum radiator and oil cooler, high-capacity fuel pressure regulator and injectors, Dinan software]
*Transmission
Six-speed manual, 3.91:1 limited-slip differential
*Suspension
Dinan springs, adjustable JRZ dampers, adjustable front anti-roll bar, adjustable front camber plates, front and rear shock tower braces
*Brakes
Dinan/Brembo calipers, vented and slotted rotors, Ferodo pads, Goodridge braided lines
*Wheels and Tires
Dinan alloys, 9.5x19 (f)10x19 (r)
Michelin Pilot Sport 2, 275/30-19 (f)285/30-19 (r)
*Performance
Peak Power: 462 bhp at 8000 rpm
Peak Torque: 328 lb-ft at 5500 rpm
0-60 mph: 4.3 sec.
Top Speed: 189 mph