gears allow you to send more cumulative power to the wheels over time. for example, with shorter gears, you go through the rev range more than with taller gears, and thus your AVERAGE HP is higher.

The gears make the car faster because each engine rotation doesn't have to spin the wheels as much.

 

It was briefly the replacement for the Cobra...I have since aquired a 996TT (X50) which is more the Cobras replacement but it's about to go soon. I love the M3 just wish it had the ooommphhh the Cobra had. I launch by slipping the clutch at about 5,000-5,500 RPMs. My car is entirely stock with the exception of DDE's and I replaced my OEM rear Pilot Sports with wider 285 30 19 Bridgestone S03's. My best runs have had 60' times in the 1.9x range...never seen lower than 1.9x.

 

OFF TOPIC:

Nice, my best 60' in my 97 Cobra was a 2.01 with 12 lbs of air in my 275/40's. The 2 things killing my mph are that I leave at 1200rpms- just above idle and I hit the rev limiter in 3rd right b4 the traps.