Wow man, i've never heard of having to remove the trany and bell to install LTs of any brand.....It seriously didnt take me 1 hour to install my LTs.
Jack up the front end, then unbolt the motor mounts and lift the engine. I used a pully type lift hanging from a rafter in my buddie's garage. One you've got the motor lifted and the old headers out, unbolt the steering column and pull it out. Then unbolt your starter and let it sit on the back of the K member. Slip both headers up from the bottom, then put in the first and last bolt for each header so they stay in place. You dont even have to put the gaskets in at this point. Bolt your starter back on, route your steering shaft through the header (which BTW, mine is stock OEM and the boot was fine after 19 years..) and bolt it back on. Lower the motor back down, or if you want this is a fine time to replace your motor mounts if you need to, since you're already in that neighborhood. Either way, bolt the motor back on and drop the car down. Put your gaskets on and bolt everything up. Piece of cake. The hardest pare was finding a garage to borrow with a hoist.
As for the HTS coating, it does get scratched up a bit. Even so, i've seen guys who have them on their cars for 3+ years without rusting so i'd say you're in the clear. For the price IMO you can't beat'em. If i had unlimited money though, i'd have Kooks headers or some kind of serious racing headers on my car. My motor is bone stock, intake to oil pan, and i can tell you the power gains were tremendous. After 3k RPM my car somes alive like no other, and there's no loss of torque below 3k either. I dont think i'll ever buy another shorty again unless it's to bolt a turbo to.
Another cool added little bonus about LTs is the mid-pipe (H,X, Pro Chamber...etc...) which i think is the biggest PITA when it comes to installing an exhaust setup. Since they're LTs, the mid pipe bolts up right there under the car behind the front wheels. If you ever get exhaust leaks at your header/H flange (which unfortunately you're going to have with MACs untill they get broke in and tightened up a few times) it's a lot easier to tighten with LTs rather than shorties.
Lastly, i think that dyno test with the shorties vs. LTs is TOTAL B.S. Think about this for a second....since the dawn of racing, full length headers have been used because it's a KNOWN FACT that they make more HP. We're not talking about the "latest fad" in headers here, we're talking about race proven technology. Everything from small town dirt oval racing, to off roading, to the local drag strip on test and tune night, to F'in John Force and his Top Fuel car, NASCAR, INDY, Formula 1, Cart, Le Mans, you name it, they're all using some sort of full length or somewhat equal length header because they flow more air and they equal out exhaust pulses better than shorties.