I resently purchased a "03" xc 600 (good deal) that has a hot seat pipe with can, EPI trail clutch kit, V force reeds, SLP air box mod kit, my question is when I changed tracks I noticed the gearing was 24/39, with this set up won't I lose alot of acceleration. My "01" 700 has about the same mods but with a 22/39 gearing and it jumps.

I'd go back to at least the stock 23-39, 22-39 would be good, but I've heard it's noisey, it's also not as efficient because of the chain bend.

Go with what was recommended for my 600...after the chain in my 05 600 loosened up a bit...we installed 40 tooth bottom year.....you have to either remove the adjuster completely or grind it to fit the chaincase.... having 23/40 gears makes the sled more responsive all the way around.

Yep, 23/40 with stock chain is the quietest/cheapest choice, and one tooth lower than stock. FYI, this was stock gearing in the 2000 xc 6 I believe.... the fast year in the old chassis.

I found stock 23/39 to be real noisy with a few thousand miles on the sled due to the chain bend against the tensioner. Both my xc 6's have 23/40, with a bit of grinding off the back of the tensioner.