I just installed the same setup on my car a couple months ago in my garage on jack stands. It's not bad at all. Tsp provides great instructions (just make sure you read them a few times before bc there were a couple parts that confused me a bit, but after I did it, it made complete sense and I was overthinking) and I didn't have any issues with the fitment at all. Got everything taken apart in a few hours at night since I was picking up my headers from being ceramic coated the next morning and would have had them installed the next day but my manifold bolt by the #7 cylinder decided it wanted to break off inside the hole 😡. I used my jack to hold up the headers and help me get the bolts started. An extra set of hands would have made the job a lot easier, but overall, not too bad doing it on jack stands.
I waited a couple weeks to get a tune. I was gentle and didn't get into any boost at all. Wanted to drive it around a few times to go through some heat cycles and retorque the bolts and clamps. The bolts were good. I don't think any loosed up except for maybe 1 just a bit. Clamps underneath loosened up a few times. I try to get under the car and check them every so often since its literally takes only a few minutes.
*Make sure when you undo the stock headers from the xpipe, let the stock xpipe hang down a bit so you have clearance to take the stock headers out. My dumb ass couldn't figure out why it was so hard to take the passenger side manifolds out from underneath for probably 30 minutes until I realized it was hitting the flange on the xpipe! I left me mufflers in place, but if I were to do it again, I probably would have just cut the xpipe first to get it out of the way.
Edit: I just realized this is in the V1 section. Everything I just wrote was for an install on a V2