I'll be the devil's advocate.

$600 buys you a nice aftermarket amp and some serious speakers probably a lot better than what BSW sells. The snag is that the install is not plug and play.

So really it comes down to how much you want to do a custom install vs. pay a lot for some plug and play speakers that are a lot better. You have to do an amp because the stock speakers are 2 ohms and you're not going to find anything aftermarket that is compatible. BSW has the market cornered and charges like they do.

__________________
2006 Audi A3 2.0t DSG apr stage 2
2002 BMW X5 4.4
1997 BMW 328ic sport. moreagrun metallic
1989 BMW 325is with / M50b25nv swap