Motorcycle Repair: 1999 YZ400F, head gaskets, corner speed

Question
I am wondering which would be my best cost-to-performance option. I am wanting to get more throttle response and out of the corner speed for short runs at doubles.

option#1) I have read about an aftermarket "piston" that ups compression from 12.5:1 to 13.5:1.  
Cost about $170

option#2) An overbore kit cost $550 machine work and new components included

option#3) A smaller front sprocket by one tooth
cost $20
I run a small local track and in the woods, for the money which would be more effective. I have the suspension set-up by some instructions off the Internet and it feels good at all points on the track.

thanks, chad
[email protected]

Answer
Hello Chad
 U have to look into the local shop's where do you live. Best cost vs performance u can get is port and polish. Bringing compression up is not always the best thing you can do to these bikes. Boring it out may look cheap now but not after all the head gaskets you have to replace the next year. Look at it this way I have a 400ex with pipe filter and port work out running 450r drag bikes. Its all about finding that set-up. What state u live in. I will like to try helping you, e-mail back at [email protected]