I've had a set of MBquarts in my 06 for two weeks now. While I'm happy with the much better definition and detail there is significantly less bottom end/bass than there was with the stock speakers. I'm hoping they will loosen up with use as people say. They have had at least 20 hours so far.

The bass issue should be fixed by a Sub. I fold the seats down a lot so waiting for someone to develop an enclosure to fit in the void for the DSP sub.

What really bugs me is that considering the cost of the X5 in Australia, the stock sound system is of such an average sound quality.

Chris