If you are running under 6300-6500 rpms go with a KB piston and opt for the higher compression( I think they are the 190). The KB's are closely matched for stock balancing. You probably won't find that with a forged piston. You'll need to pay for the rebalancing. I don't think you will be making any power beyond 6000 rpms with those heads.
I'm running the KB190 currently and I believe the wrist pin hole is the point of failure. That's what I'm replacing them. They have roughly 25k mi and hundreds of passes on them. The majority of use for the engine is at the track nowadays, so I need toughness and reliability.
