Berglez has the rally championship tracks in .max format here which will open in 3dsmax, or alteros if you just want to look at them. The thing about rally championship is that the stages are real so they can be easily mapped in google earth. I've mapped all of them so far and am working on Clocaenog mid as my main project because it's quite close to where I live
Are you planning to import those stages to RBR? I remember that the stages were pretty realistic and it would be great to drive them in RBR.