cosmetically, my 8 definitely wasn't delivered as flawless as my 323 was- namely because mazda dealers just don't handle vehicles as carefully as bmw dealers do. but, having taken delivery of both cars new, i offer a slight difference of opinon...
the interior design of the 2 cars is totally different. the bmw is spacious, elegant, & luxurious, whereas the 8 is more cockpit-like, sporty, and sleek. after all, one is a luxury car and one is a sports car. (apples to oranges here.) but, just because a car isn't a luxury car doesn't automatically mean it's going to be cheap and sucky.
as a bmw owner, i have pretty high expectations i think. but, at the same time i can be very objective too. and, quite honestly, i never once felt that the 8's interior was cheap or flimsy. otherwise, i would've hated it. in fact, i was very surprised with what a great job mazda did in creating such a simple, sexy, two-toned interior. the sportiness flows throughout the dashboard + console. and, the minute i climbed into the cockpit, i could feel my heart pumping and wanting to take this thing out on the open road and push it to its limits...
if u want an example of a really cheap & flimsy interior, then check out the pontiac solstice or saturn sky. now, there is a car that i cannot figure out. the outside screams sports car, but the inside is like, "sorry guys, we not only have bad taste and don't know how to design an interior, but we also ran outta money to try."