hey guys. i ride mostly on logging roads that are for the most part wide open with some small hills, and most of my friends have 400's. what size sprocket would you recommend to keep up with these guys? also, are rev boxes worth the money? if they are, what brand should i get? thanks for any replys.

 

If wanting more topend go up to a 14 or 15 on the front.

 

if i get a 15 tooth sprocket, how much bottom end will i lose?