Hey there!
I've done the bug tranny + engine drop before, and the same on a 911. Good idea to do the mating before install! I think it's a the better way, although harder to do alone.
The 911 is easier by far. The reason is that you don't have the "forks" that extend from the tunnel like on a bug. The 911 unit just goes (practically) straight up and attaches with four, easily accessable, bolts.
If you can do a FWD Rabbit, you'll have no trouble at all!
I recommend you take the rear body work off, like the sheet metal that the license plate is mounted on, and bumperettes if you have them. That will completely fix your fan/fuel system clearence issues. You'll need to get whole thing up, then move it forward to get the shift rod into the tunnel without banging it up. The rear sheet metal removal gives you more fore/aft clearence, helps a lot.
My biggest lesson learned: although it is possible to do the job with just the back jacked, I think it would be MUCH easier on 4 jacks. I had to wrestle my engine to the same angle as the car, it was a major PITA. I did my install alone: also not recommended. You'll be fine, you have more room under the P-car than you did under the bug.
Good Luck! You'll be fine!
-Dan