Ive read all the discussions regarding swapping a 6spd trans into a TBSS and if there's a way to do it I want to know. There's a chance I might be getting one soon myself and yes the 4L70E shifts much better than the regular 4L60E in the regular TBs but the 6spds are just so much better. Plus 2 more gears is a bonus! Ill be watching this thread like a hawk, but I understand XLR8NSS's dilemma, to go through all the hassle of swapping a 6L90E in then not being able to make it work because of ECM/TCM comm probs would flat out suck.