interestingly enough, most GM obd2 PCMs can support DBW throttle bodies. the 0411 does it with the corvettes, and the PCM's used on most of the V6 cars do it on the later V6 4th gen F-bodies. I also don't see why the V6 PCM couldn't support a returnless fuel rail too with the right tuning. I think many of the 3800's use a returnless rail. I'm pretty sure the 0411 does out of the box.