Trek tunes the frames to ride about the same regardless of the carbon used. The red/black/white carbon bikes should ride about about the same the higher end will mostly be lighter. This may or may not be a good thing, as they could tune each bike to ride however they wanted, but because they are Trek, they try and get a good balance on all the bikes.

As for Pro/Performance, the Pro is very close to the old geometry, so if you could find a pre-'08 that might help with fit. I'm not sure how close the 5200 and older Madones are, but you could look at the geometry and get an idea. If you run a big stack and an upright stem, the performance fit might be better, but if you have no spacers and a level stem, they Pro is the way to go.

As for 5.2, 5.5, 6.5, depends on budget. The 5.5 gets you Sram, and the 6.5 gets you Dura-Ace, better wheels and carbon, and a few other improvements.

If color is a big issue, Trek just reopened the Project Ones, so you could order the exact bike you wanted. That said P1 only come in Red carbon (Pro, Per, WSD).

http://projectone.trekbikes.com/

Good luck, fun problems to have.