Don't bother with Race Pro if you got a decent PC. Get Race On instead. PC is the still better when it comes to racing games.
Here's some PC advantages:
1) Triple screen support for every single racing game including older games.
2) Most support TrackIr (if you don't have triple screen)
3) Mods which improves the game like AI in F1 2010 for example
4) You can use more than one controller device , for example I can use my CSP with my G27. (At least now Gt5 allows using both a controller and wheel)
5) For the most part PC sims focus more on physics than graphics. Rfactor/Iracing (Also PC sims are design more with a wheel in mind while consoles with a controller. GT5 may be an exception.)