Anyone know what I should expect?

My motor is stock, for now (416 or 426ex in the near future), UNI air filter.

I plan on getting the full LRD pro 4 system (its used, but good condition, and cheap).

Rejetting for the pipe..

I am told to expect a little lose of low end torque, but stronger pulling through the entire powerband?

I race my buddy's piped Raptor 660 all the time, and I can actually stay with him, sometimes he blows me away if I dont hook up (my stock rears are SLICKS!.. got 22" holeshots on order). He thinks my stock 400ex could give a modded one he rides with a run for its money.. Im 165lbs, which might be a factor for sure.. Last night we raced on a 300ft straight dirt road, i HOOKED up hard and stayed ahead of him till i maxed out 5th gear then he ended up pulling slowly [img]i/expressions/face-icon-small-tongue.gif[/img] he wasnt so happy about that, because he always talks about how fast his is and how he kicks my 400ex ***.. he had a weird expression on his face when he lost.

I gotta slowly but surely modding my EX to walk with, or walk past my buddys 660 (consistantly) [img]i/expressions/face-icon-small-tongue.gif[/img]