T5 vs T45....

[Mustang5L5]

But when does the case become an issue on a daily driver? ..also isn't their some problems that the g-force trannies have?

I would never really consider case failure an issue with normal daily drivers. You're more likely to blow 3rd or input shaft way before the case blows.

I've heard or initial problems with g-force due to wrong or inpure materials properties in their parts but lately i think they have fixed the bugs. Everything breaks, but i think their reliablity issues are improving over time. Most of the failures i have read about lately are from drag-oriented slick cars with 400+ HP launching at 5000RPM and powershifting.