Probe, Diamond, SHM, ModMax, Manley, etc. Pretty much all of the major players are making pistons for the Mod Motors now. If you're going to swap them out, don't waste your time or money on anything but forged slugs. Power gains could vary depending on additional bolt-ons and breathing mods. But a jump from the stock 9.2:1 to 10.5-11.0:1 might yield 10-12hp on an otherwise stock engine.