Don't go with the C4 - it's light, but not as strong as a TH400. The TH400 is the best option, and still has some street manners.
I just switched over to an AOD. I wanted to retain overdrive, so it was really the only option. It eats up a ton of power, but that is a sacrifice that I decided was worth it.
Higher stalls usually result in faster times, but make it more aggravating on the street. I decided not to go with a high stall, but still went non-lockup.
A good valve body is a must. I went with one that still works normally in auto, but allws for good manual shifting, with reverse lockout, and ratcheting to keep me in the correct gear.
My new transmission setup is very streetable.
I'm still dealing with cooling issues, so I'm working on that now. My front bumper seems to be blocking too much air.