I've got an '85 318 and a Darth Vader ('88 750il) My oil filters are more expensive, but the few parts I've bought have been significantly less than anything comparable that Charley's had to replace on his Toyota - and there's no comparison to my parent's Passport. My friends who have Japanese cars cringe when I show them the difference in the price of parts - and that's AFTER I hook 'em up with my import parts guy, who has better prices than anyplace else around here.
Plus, I didn't need a complete engine rebuild at 105,000 miles, like Charley's Toyota, or a new alternator at less than 100,000 miles, like the Passport . . . The little Bimmer probably has 300,000 or so on it now and runs like a top, but BMW has been building that 1.8 litre power plant for probably well over 40 years, and it's basically bulletproof when coupled with a 5 speed.
Now, the Porsche parts are a different story, lol! But there isn't as much difference as you'd think!