Hey bro, welcome to the board and congrats on the Monsta! I've got an S4 and I think personally the biggest improvements I noticed were the least expensive Lightened flywheel, slipper clutch or cheaper-get a lighter clutch (basket,etc), wheels. I installed cams/pistons and got a new PCIII, but nothing was more noticeable than the above. Wish I was in S.Cal, but I'm up North of you. Good luck w/the bike. You'll find the people on here (if you haven't noticed already) are more than willing to help out and give great advice...