I use to have a 2000 DS 650 with an FMF slip on. I repeatedly raced a couple of my buddies shee's on pavement and they both were running toomey's, K&N, coolheads, and had been ported. The DS is extremely hard to beat on pavement due to its weight and size. You can drop the hammer right off the line and not worry about front end lift. Everytime we raced I was gone before the shee's could get off the line. My advice is definately go prac. getting some launches on pavement! Most of the time the better rider will win the race not the better quad.