29 A-spec
36 B-spec
I've come to the realization that there is no good A-spec grinding. If it's credits you're after, then the B-spec Dream Car championship pays a million, for around an hour's work, and you can go off and do other things. The American A-spec ring, gives around the same for 45-50 minutes of work, but you have to drive it yourself... and that gets boring quick. The B-spec endurances are good for overnight xp, but I can't bring myself to do A-spec endurances. The only way I advance now in A-spec is with the seasonal events. Otherwise my time in GT5 is now spent with B-spec credit grinding, in order to complete my garage.