not to derail this thread, but I have a garaged 1993 Caprice with the OG engine in it, I couldnt even tell you how many miles it has. Granted I dont know too much of shit about the mechanics of cars, but with regular maintenance (i.e. tune-ups, oil changes, leaks here and there), that shit rides like butter. Only when I first got it in 06 is when I had to do a little bit of replacing parts every now and again.
So with all of my current vehicles being foreign, I took it upon myself to learn the basics of replacing/fixing mechanical shit that people say is usually expensive to do. Plus, I'd assume if dude is lookin to buy European, he doesnt too much mind the cost of maintenance. Yes, it costs more on average to get foreign cars repaired in America, but if you find a spot that can do it for a good price, then start appropriating money for shit like that anyway.
I think out of the two, the Audi would prolly be more expensive to patch up in the long run (having had a 98 A6 once upon a time). But Bimmers are easy man.
Again, this is all coming from a novice with shit like this so take my word, or anybody's for that matter, with a grain of salt.