FYI the genuine 313's have a bmw cast mark on the hub and are made in italy (I cant remember the manufacturer them but it wasn't BBS it starts with an M by memory.....- I will check this tonight when I have my rims off)
Also I believe the 19" 313's are forged items, whereas the rep 313's would be cast wheels. Generally what this means is that the crystal structure of the rims are larger in a cast wheel which results in a weaker microstructure, whereas the forged microstructure has a crystal structure which is a lot finer which resists fatigue & impacts.
This isn't info I have regurgitated from the net, I actually work as a metallurgist for a co who manufacturers forged wheels (alas for trains not motor cars) and cheaper cast wheels is becoming more prevalent in our market as the cheaper purchase price lures customers but in the long run it ends up costing them more as they have to change them more often and failure rates are also higher.
Last edited by DR-JEKL; 12-13-2012 at 10:05 PM.