As the guy that helped you fix the diff and in a sense kill the engine...i'll weigh in.
1. Have your "connection" source you a low mileage motor from an 04-08 GP, or Lucerne etc. Locally I'm paying $300 for low mileage NA motors.
2. Swap the rear exhaust manifold with yours, get a TB adapter from Gen V to L67.
3. Buy an L67 TB and get your pcm programmed for the change in maf tables
4. Drop on that Plog and DP
5. Put in the HV3
6. GT1 cam actually does a pretty nice job in an NA, it's not worth it IMO. Cost vs power isn't right.
7. Realize I know what I'm talking about.. I'm driving an NA Regal GS (that's the SC'd model) with 2.93 (stock SC tall gears). It's faster than most think it should be. Only mods.... Plog, DP and L67 TB.
