Cryo treated, stronger root/tooth profile, stonger than stock, but not a very much stronger. I've heard up to 300 WHP tossed around, which for the money (~$2000 before install) doesn't sound too great. The general concensus seems to be that if you're shooting for big power, don't bother with the RA gearsets. I was thinking abut the RA sets because of cost, but I only want to change gearsets once. Don't forget about the transfer shafts/gears and the mid and rear diff, they're weak too..