When we test drove a BMW 381i Touring (wagon) I took along my iPod which stopped working after one song. The salesman said they were incomparable with BMWs and suggested I get a newer iPod like a Touch. This was very bad news as the iPod classics are much bigger than the new ones and I need space because I put wave files on my iPod to get the best fidelity.
We ended up getting the sports version of the 381i, with a better sound system, and my iPod seemed to work. However, on a recent road trip, the iPod finally started disconnecting.
Fortunately, there was a fix for this, rebooting the iPod by holding down the middle and menu buttons at the same time until the Apple icon appeared. I had read on the internet that this would work, though for some people, it only works for a day. I had to to it twice on a three week road trip.
The car also comes with a hard drive, but the hard drive only takes compressed files. The sound system also takes USB sticks but there seems to be no way to use Shuffle (random) with a stick.
Actually, I can't figure out how to use Shuffle with my iPod but if I set it to Shuffle before plugging it in, that seems to work.