Ok here's the deal, I have some JE pistons for my GSR motor and I just sent the block off to get it sleeved and was planning on going bigger, they recommended 83mm so there's still room for repair if anything goes wrong. My question is, will I see that much of a gain in 2mm bigger pistons or should I spend the extra money somewhere else? I was thinking bigger valves but might not be able to afford them if I buy the bigger pistons. Will there still be a good gain with bigger valves and 81mm bore provided there's good port work to go with it? Thanks for any input.