Yeah, I intend to. A lot of guys on here have swapped to the manual transfer case from the F-150 but kept the 4R70W (it's the same trans in both trucks). Doing that, the shafts would need to be changed so they bolt up to the different t-case (as well as because of a a different length on the T-case).
What is clear though is that either T-case will bolt up to the 4R70W and respectively will both bolt up to the M5R2. If the driveshafts are the same between the 5 Speed F-150 and the automatic F-150 then my driveshafts shouldn't need to be changed either. I'll have to do some digging into it and see.
Incidentally, I'm not really into bracket racing or drag racing. It's a fine reason to not use a manual transmission in a sports car. But that's life a 1/4 mile at a time. I'm much more concerned about gear ratios and what happens when shifting from 5 down to 3 or 4-3 or 4-2 or 3-2 etc. I'm really not even into Mustangs. They are pretty good for going straight a 1/4 mile at a time but not much else.
My other car (which just sits collecting dust with cracked heads) is a 97 Pontiac Formula Firebird. For a car that's gonna downshift, take corners ridiculously hard and generally run amok on the expressway, it beats the Mustang in almost every respect. This is where my liking for Borg Warner's T-5 and T-6 comes from (even though they are used in Ford and Chrysler cars as well). These transmissions are not geared to pull trailers, stumps or haul a load of gravel in the bed. They are built for aggressive driving and down shifting. I think the T-6 was available in the F-150 lighting coming to think of it but I doubt it bolts to a 302 or has the proper tailshaft to take a transfer case. I really don't wanna spend the money on a T-6 anyway, set ya back 3k at least. T-5's are cheaper, but if they never made it work for a 4x4, it'll get dicey having to get a custom tailshaft and tail housing (more money than I wanna put into it).
It's all about gear ratio's though. Transmissions meant to "go fast" use different kinds of gearing to keep the ratio's closer to one another. Truck transmissions usually have a granny gear (even if they call it 1) that really isn't necessary unless pulling. Usually that 1 is lower than you'd find in any other kind of trans. It'll jump better than a racecar trans will, but has to make a bigger gap between it and 2nd gear (meaning your revs drop harder after the shift). That's a trend that continues all the way through drive (4).
This of course opens up a whole other animal of concerns about the M5R2 and whether or not I'll actually like it in the Expressway Cruising Explorer that I have. I'll have to look into the gear sets and see where they're at. I may not like them at all when paired with 3.73's in the axles. I may like them better with different differential gears. I may not like how far apart the gears are in general. One can always change the gears you'll find in any given transmission, but then that ventures into a lot of money I may not want to spend. Could likely work out that I could change the tailshaft/housing on a trans I do like for much cheaper.
My dad always said, "Speed costs money, how fast do you wanna go?"