Actually it matters a great deal.
Aftermarket changers will likely need rewiring via harnesses & adapters to function. Believe BMW audio was more widely compatible only until the mid-90s. It'd probably only make sense to do this if you're doing an entire audio/video changeout to aftermarket.

For Bimmer stacks, there's IBUS or non-IBUS (different connector pins) and MP3-compatibility to be concerned with. I don't have model #s (sorry), but know that you could either end up with a connector that doesn't fit (worst case) or no MP3 support, which is annoying if you carry burned disks with you. I went through that whole assessment a couple months ago, and I know there are threads and articles here that spell it all out. Search "cd changer" on the homepage, and