Hmm...Well if it's an office style job, you could get him an office style gift. He seems to like cars, so why not something like this
gear shift pen holder? Or you could get him a toy car. Go by toys-r-us and see if you can get him a toy version of one of the cars he owns, it's a great little desk conversation widget.
Or you could do the "basket" thing...Get a wicker basket and go by a grocery store (someplace like Whole Foods would be great) and stuff the basket with stuff he likes, a bottle of wine, some green tea bags, maybe chai tea mix, and throw in some healty-conscious dog biscuits to round it out. Stuff the basket with some tissue paper and you're good to go.
Since he doesn't need anything it sounds like food is the way to go, and anyway it's always more thoughtful than gift cards when you don't know where he'll want to go. I suppose $30 wine isn't a great gift by itself, but they make those cheese and sausage spreads, you could do that. Oooor what about a wine bottle stopper? I found
this after about 20 seconds on google, with a bit more effort you could probably find something porsche-and-wine themed.