Take a look at the articles section. One problem you may run into is the plastic 'baffles' that the stock speakers are located in. You will either have to cut out the speakers from these plastic molds or fabricate your own. The aftermarket speaker may not screw directly into the door panel without some sort of modification. Secondly the stock location for the tweeters may limit which tweeters you can put in there. Again I have seen some mold a plastic piece which will hold the speakers. If your 'kit' is specifically designed for the X5, then it may not be an issue. Be sure to post pics...