What would You Choose and More Importantly WHY?

T5 has a useless first granny gear, Its very notchy compared to
a A833, if the car has any low end wont need T5 , and an engine of this power wont be able to pull and 0.68 over drive
in hilly roads.

My 75 F250 has a 6.72:1 first gear and I use it every single day. Far from useless.Irealize it's a different application, but nonetheless......

Have you ever had a T5 behind a slant? I have a friend with a T5 behind a Ford 250 straight six in a Maverick. Stone stock. ONE BARREL. It's a really neato ride and does none of the things you suggest. It's a fair comparison, which is why brought it up.

Wilcap says they can make a bellhousing for around 1200 bucks. It ain't cheap, but it would certainly be different.