If you are looking to buy NEW parts locally, Joe Kirtpatrick's place in Cleveland (I'm having a moment here and can't remember the name of the place for nothing . . . Tri-State something? something Tri-State? . . . ) or American Foreign in Dalton, or Al Johnson's VW dealership in Dalton all carry a lot of air-cooled parts and can order about anything you would need. Mainly Foreign in Chattanooga carries a lot of air-cooled parts as well, but tend to be a little more expensive than the other three places.
For mail order, I've used CIP1.com and Mid America Motorworks and always had good luck with them. There are a lot of other good mail order places out there, and a lot of bad ones as well. Be careful with mail order because there are some really sorry aftermarket parts out there . . . and with mail order, they've got your money long before you have the parts in your hand.
Swap meets are usually the best places to buy . . . mail order prices, usually no tax on the goods, you can see what you are buying before you hand over the cash, and there may be 4 or 5 vendors selling the exact same part trying to get your business.