If you're going to buy any pistons at all, you may as well buy some that will raise compression. There are plenty out there to choose from. I would keep compression at 9.3:1 at the absolute most. This seems to be kinda a magic number for non quench engines, which yours will likely be. Plenty of compression to make gobs of torque, but not so much where detonation is an issue. Expect to run premium gas though, if you want anything that resembles a performance timing curve.
