I think ht e999 is the one with 5 clutches already in the front pack and 4 in the rear, if so it is the good one. It should have the low 1st and 2nd gear ratios in it also, if not get a set. The low ratio works great and is the strongest factory set of pinions, 4 planatary gears in a steel cage.

I would build it with a trans go kit, witch one depends on how hard you want it to shift and if you want it to still shift automatically, I personaly prefer the TF-1 kit with the setting set for max firmness.

As for the rest of the trans I like to eliminate the wavy snaprings in the clutch packs, put a spacer in the rear band apply servo to make it solid, put a blocker rod in the middle accumulator to keep it from moveing, make sure you have at least a 3.2 ratio lever up to a 4.2 don't use the 5.0 and filler up with some type-F fluid and it should last a good long time.