Z06 hands down. Although the M3 is a great car for everyday driver and I'm sure at the track its a great controllable car satisfying looks with a little speed. The Z06 will just put a big smile on your face. I sold my E92 M for a family SUV... leaving extra money to get another toy. I got the bug for speed again while looking for a Z06 I came across a 98 supra that I did a single turbo conversion and re tuned for 620 HP to the wheels. I can tell you I never think about my M much anymore this car is crazy strong and to think I was going to spend 10k on a supercharger only to get 500 hp and worry about blowing it every time I start the car. I can smack on this thing all day and only worry about tires. The Z06 is a great car all you have to do is drive it and you will be smilling ear to ear.