There def is faster "FI" M3's out there. 320WHP NA, stock internals? Sounds like a happy dyno for sure. When all I had was 3.91 gears, and BHS pullies, I ran even with a car that had just about every bolt on available with 4.10 gears, bolt on mods do very little, traps and comparo's indicate this.
Can you take procede 335I's or
Not a happy dyno...my M3 put down around 278 RWHP stock and my 335 did 281 RWHP stock. Obviously the 335 has a huge torque advantage and my M3 has pretty much everything short of cams and traps around 111-112mph. My 335 put down almost 345 RWHP and is over 400 lb/ft and it still pulls my M3 from a roll especially under 80mph or so. The M3 still pulls up higher especially in the triple digits but it's also about 300 lbs. lighter than my 335. The hole shot is all about the driver but my M3 is easier to launch but it has bigger stickier rubber on it too.