Didn't know about the HTT when I did the ATS on mine, may not have even been available then??? Anyway, the ATS was a PIA to get together. I put the end pieces in the freezer and center section in the oven as suggested in the instructions. I even antisezied the connections and still had to pound the **** out of them to get together. It's all good though as it aint commin apart now. I laid the old manifold on a piece of sheet steel, scribed the bolt holes through and onto the sheet steel as a template to line up once the ATS started to go together. The sheet steel, about 1/16th" thick, acted as a flat surface in addtion to lining up the bolt holes it helped insure the head mating surfaces were flat for install. I guess it's been on for more than a year and I'm pleased with it. Could install have been easier? yes. Was fitting it together easy? NO. Could the installation instructions have been more clear? yes. Was the finish acceptable to mount? NO - It would have rusted immediately. I sprayed with brake-clene to remove the protective shipping grease (cosmolene-spelling?) and painted with Eastwood's exhaust paint - still looks as good as the day I put it on. Just wish I would have done the turbo while it was off. All in all - I'm satisfied with it's performance, it looks real beefy. I wish the bolts were not allen heads, made for a difficult time with tightening the bottom bolts.
MHO. From what I've read in this post, if I knew the HTT was available I'd have probably gotten it instead of the ATS unit.