Good write-up. It's pretty much spot on from my experience. I'm really looking forward to see others opinions as they receive theirs and have them installed.
Since you mentioned the N51, I'd only add that it is a bit more work to install, but nothing too dramatic. The OEM pipe after the resonator on the N51 is a larger diameter. So the clamp won't work as it won't fit around the OEM exhaust. The solution in my case was to cut part of the AA exhaust off that had the clamp on it and weld it to the OEM pipe. The rest of the install was the same. I'll post some pics in my own review.