it depends do u have a stock esc what turn lomit is it rated at if u want all out speed then id rec speedgems or reedy 9-10 turn motors with a 15 t pinion gear
orignal rc10 with 9 turn speed gems motor with15t pinion gear tekin 410s2 esc and gp3300
http://www.rcpics.net/media/Mov00015.mpg
http://www.rcpics.net/media/Mov00014.mpg
http://www.rcpics.net/media/Mov00013.mpg
http://www.rcpics.net/media/Mov00011.mpg
losi xxx with ripmax xtra esc reedy 10t motor with15 t pinon gear adn gp 3300 bats
http://www.rcpics.net/img/72567
http://www.rcpics.net/img/72561
http://www.rcpics.net/img/72559