I bought my GM Delphi optispark distributor from thepartsladi @ e-bay, $250 to the door. Now the one before that was from a no name parts supplier and it crapped out on me after about 90 days! The original GM optisparks IMO are the bEST best out there, just don't buy it from the parts store or GM, OVER PRICED as usual! I know guys making 400-500+ hp with these optis with no problems.