I've been looking into speakers to replace the harmon kardon ones in my '98 m3. anyone have any experience with CDT audio? also what sizes will fit. a local store told me i would have to do some cutting to fit most speakers in my car. thanks

I don't know anything about those speakers, but as far as the sizes, you can easily fit a 6.5" in the kick panels with some cutting. For the door speakers, you can fit a 4" mid and 1-2" tweeter. The 4" has to be somewhat shallow though because there isn't much room behind that part of the door panel. You might also have to cut a small piece to fit the 4".

If you don't want to do any cutting, you can install a 5.25" in the kick panels and go with just a tweeter in the door. I've used that setup many times, and it sounds fine for most people. Hope that helps!