Official Rules Available here, also be sure to know the NDR Sporting Code.

FINAL Changes for 2013:

• Entry requirements reduced to simpler levels, although there are separate Road and Oval licences still.
  
• Removal of Owner's Championship, Rookie Cup, and Qualifying Trophy
  
• Re-introduction of compulsory pitstops.
  
• Shorter Races (250 km v 320 km from 2012)
  
• Superpole eliminated
  
• No upper bound on number of cars representing a team, top two finishers still score the points.
  
• Nation's Cup score now takes average of the two best finishers for a nation per race.
  
• Entries are now to be DRIVER based, not TEAM based. A driver will be responsible for his car and his car only.
  

Quote from dekojester :

Removal of Rookie Cup

Why?

Most likely to lighten the load on admins. All the other calculations are just time consuming. In the overall points a simple * could designate a rookie and have them find this information on their own.

I understand removal of useless owners cup and time consuming qualifying trophy,but rookie cup? Still sort of interesting fact to know who's best newcomer and a great reward to the rookie himself.

The rookie cup table itself was simply the driver's championship minus non-rookies. I'll add a rookie flag to any rookie's entry for this year, so you can easily see the rookies in the driver's championship table (and by extention, all other driver-based championships)

The rules book for 2013 is now final.

Please note that the Signups Lockout is now shorter, taking into account the use of a web-based entry system that can more or less handle itself.

Why are R4 tyres banned for road courses?

Probably to involve more strategy

Quote from Storm_Cloud :

Why are R4 tyres banned for road courses?

Because r3 is hard enough anyways and renders r4 useless

Quote from Storm_Cloud :

Why are R4 tyres banned for road courses?

So tyres [sic? ] don't become ice cubes in caution periods. Same reason why R3s are banned on ovals

Quote from J@tko :

So tyres [sic? ] don't become ice cubes in caution periods. Same reason why R3s are banned on ovals

No, not sic .

That makes sense. I used to have a couple of R4/R3 FO8 sets which were nicely balanced and used for sneaky no stop strategies. It would be a nightmare after a caution though!