Follow-Up:
I have that same engine too. I always use premium gas. VW suggests premium, but does not require it. I've never tried regular gas. Experienced automotive engineers (I live in Michigan) say that if you don't get knocking then you can use regular gas. I use the the premium because it has more detergents and the engine management unit (computer chip) detects the difference in knocking before you can and sets the various engine settings to maximize power and efficiency based upon the fuel being used right then (according to current engine conditions). Besides, spending more on gas makes me feel better. Very truly yours, Jeffrey Zoeller