I'm not very familiar with r2p site structure so far so I'll try to maintain the list of interesting quick-links.

Feel free to add new ones in the comments if you know something :)

PS I've collected all the links from comments in this first message for the comfort's sake

Supported mods downloads & race replays

Track Records

R2P Help docs

Craig's "Set-up help" blog - quite a few interesting links about setting up your car.

Ray Gillespie's "Guide to Surviving Sim Races" - general guidelines on how to race a car. Could be interesting even for experienced drivers.

Overly aggressive driver? - very interesting thoughts about driving etiquette in Tim's blog.