Stock for stock the E93 M3 is slower than a X6M
http://www.fastestlaps.com/compariso...-bmw_x6_m.html
On the other hand, the E92 M3 is indeed faster than a X6M stock for stock
http://www.fastestlaps.com/compariso...-bmw_x6_m.html
But a simple chip tune on the X6M and the game is over for M3...