Camaroguy1998

Ok so I have a 98 Z28 as my project which I have a long list of stuff i want to do it over the years and my biggest issue I run into is PCM I want to get a 2002 PCM at some point but I also want to do a A4 to M6 swap too so if i did lets say the trans swap and did a rear end swap(prob moser 9 inch) and that's all I did at the time would it be best just to send my PCM to be tuned for the gear ratio change and trans swap? Another question is if I later on when I rebuild/ mod the engine would it be best to do a PCM swap to a 2002? If so what would i do about VIN #? Would it have to be a 2002 camaro ls1 m6 or could i use a 2002 camaro ls1 a4 vin? I'd end up having it dyno tuned but I'd like to at least do the basic tune myself to get it running. I know i'd have to re-pin the wiring harness and fuel gauge won't read right but I was thinking of just doing a autometer gauge that has a custom sending setting, plus I'll end up doing all after market gauges to make things simple. Also I know the BCM has some things it will not like too, so if i re-pinned the BCM for the 2002 camaro, and then bought a new never used BCM for the car would that help me not have any VATS issues?

I'd like to keep ABS and VATS if possible. Also my camaro does not have ASR/Traction control(thank goodness).

Just trying to get input so when i go to do everything I do it the right way even if it does cost more money.