I have a very similar set-up on my trail bike.... HJR dune port, .20 over, VF3, stock carbs, no airbox lid, pro design head with 20 cc domes, +4 timing, 145 compression. I actually switched from cpi's to T5's. We do a lot of technical trail riding and rocky hills. Best move I made. I love them, and I made money in the switch