Haltech or Accel DFI?
The new Halltech (EG6M I believe) was supposed to be a plug and play unit where you'd remove your old ECM and plug this one in its place. As far as I can see, it's yet to be proven, but does appear to be a good idea. The hot item in terms of programmable ECUs would have to be the Big Stuff 3 (http://www.bigstuff3.com) which adds native 4l60/4L80E control and self-tuning among its list of impressive features. It's also not cheap at all.
What is your current setup? You don't need to step up to one of these units until your setup is fairly radical (low idle vacuum) or when you want wideband O2 tuning.
Ron





