Best VIN to start with on P59 ECM with my combo?

[Hotwire]

Received an ECM with my engine that was programmed for the seller's other car, so right now I've got an SD tune for a turbo with 4L80e.

I haven't burned any credits and need to know what VIN / drivetrain setup would be best for my application and ease of tuning?

1964 Chevelle 4 door
2003 LQ4 from 2500 Express Van, P59 green/blue ECM, DBW intake, stock for now with return fuel system and long tube headers
2006 GTO T56 6 speed trans
electric fans

I have not started wiring, tuning, etc. This combo can change.

Should I stick with a truck tune or switch out now to a car tune? Is one easier than the other? I plan on finding a 03 truck MAF as well.

At some point I will be installing a cam and a/c, but that's about as far as I'm planning to go with it. Any help would be greatly appreciated.

[Hotwire]

Bueller? Nobody has input?

[ScarabEpic22]

What OS is in the PCM now? Is the PCM from the Express the LQ4 came out of? Stick with whatever is in the PCM now so you dont have to spend 4 credits to license your PCM (2) and the Vette tune (2). If you're ok with spending the extra credits, use a Vette base OS w/manual OS. Otherwise segment swap the manual trans into the truck OS and be done with it.