any differences between the models and is it a straight swap?. I have heard thats trans work differently between ABS and non abs models?

and whats the go with AU 5.6L te/ts50 having a torque reduction between gears?. is this in the tune, any way of putting this into an e-series BTR?

Also would an AU V8 trans fit an EB?

YES and YES the lower sump bolts won't line up but with near std power levels NOT required..
You can fit or swap the E series housing over onto AU BTR ...