I've already decided that if I have the money, when my my 700r4 finally bites the dust, I'm converting to a Tremec TKO 5-speed (the one w/3.27 1st). I would like the T56's better if they had four underdriven gears, one direct, and one overdrive. Who needs double overdrive? You could get a Richmond six, but that's big bucks. And close ratios boxes aren't approprate for trucks with torquey engines IMO. The TKO has a GVWR of 5500 lbs (based on last generation rating) vs. max 4000 lbs for the T56 (depends on version). On top of that the TKOs offer more shifter mounting options.