Im new to upgrading engine internals and was wondering what kind of boost in HP
new higher compression pistons would produce, i found that my 2002 has 9.1 to1,
and the ones i found were 10.7 to 1. Also if i put in the pistons would i need to
upgrade anything else while im in there?
eg. intake and exhaust cams?

 

Your primary obstacle will be fuel and ignition mapping. That's where you need to start with the dilemna. If you can find a feesable way to set these parameters than I believe you should be fine with the upgrade itself along with the cams, both intake and exhaust.

Rishie