I have to say I'm surprised at your choice of transmissions. While the T5 is light weight, they aren't known for their strength. While there are aftermarket T5's that are stronger (such as the GForce), I'd have recommended a Tremec TKO-600..
Here was my logic for trans selection.
By 1993, the standard Ferrari 348 was making 310 HP@7200 and 237 ft/lbs@ 4200.
That was with cats and all emission crap and they weighed 3000 lbs.
I’m doing some internal motor mods (head work, cams, hi-comp) and no cats, but my intake will limit me some. I hope to make around 350HP and 250ft/lbs. The T5 is more than enough to handle those numbers and my car should be less than 2500 lbs.
I’ve even decided to run a Ford 7.5 rear axle instead of an 8.8. The 7.5 more than handles the power and I don’t want to add weight.
I wanted a bellhousing that generally matched the Ferrari block. I found all V8 bells were so large that they came up higher than the valve covers, really ugly looking. The Ford 2.3 bell was the perfect size, and came with a T5 pattern.
Also I can get the ratios I want, several tail shafts to place the shifter anywhere I need, and as you mentioned, it’s only 75lbs total weight. Plus compared to the TKO, these can be had for cheap.