I used a Saris bones rack when I had my mini. I loved that it attached fully to the back hatch, so that I could easily open it with the rack on it (I even did it with my bike still on it, but that was nerve-wracking!).

You did just buy the best car in the world. I'd give anything to have mine back.

Anyway, don't be intimidated by the 'trim the heat shield' thing. I had to do that to install a hitch on my Prius and it was no big deal. I don't know anything about any additional straps though.