Okay, so the 4l80e is going to be a better choice, and the standalone ecm's are awfully thrifty right now. Advanced adapters can adapt any GM OD Auto to pretty much any transfer case you can think of. You'll be pissed off at the 700R4 in no time flat. No matter how cool you keep them, they just eventually find a place in the pile of 700r4's behind the garage. The cool thing about the 4l80 is you can get virtually indestructable sprags and the big 32 spline output is really the only way I'd ever go, especially if you're going to upgrade to a 205 transfer case, or the venerable Lowmax 3:1. There are tons of articles detailing 4l80e swaps in trucks. And for the record, the Compushift is the best unit ever built, and you can unplug it and run it in any truck/car you have with a 4l80e. Its really nice to have your transmission pulling braking duty downhills, and you also have a temp sensor bung that can be drilled if its not already. Good stuff. You'll go through far more money playing with 700R4's, hence the 4l80 in my m1008 and the th400 behind my 454, lol.