all w-bodies have their ECM/PCMs underhood, has nothing to do with OBD2 requirements. it'* kind of unique, since the only other vehicle platform i can think of that has almost always been underhood was the corvette. that went underhood in 1990.

the 94-95 3800 Regal PCM is identical, save for connectors and case, to all of the other 94-95 3800 applications. where they connect on the PCB is slightly different, but the board itself where all of the discreets are is the same piece of hardware.

Ahhh, thanks for the clarification.

I would love to go with a tuneable 2.0 but wouldnt I have to change wireing harness?

your existing PCM is tuneable... but i wouldn't know about having to swap harnesses. i could send you some diagrams if you want to determine it yourself?

I thought 1.5 were locked or untunable.

the 93-95 3100 is.... but the 94-95 3800 (be it L27, L36 or L67) is tuneable...