[jtdavid]

I recently had the Bimmertech speakers, subs, and amp installed. It made a significant difference. Definitely an improvement over the base X5 and even over the HK audio I had in my previous car, an M2. Much clearer audio and no distortion as volume increases.

The installer I hired installed the amp first and he said just doing that made a big difference by itself.

If I were doing it over I would probably buy the Bimmertech amp first and install it and see if that was good enough. But I do have a feeling swapping out the subs and tweeters made a difference as well.