I had a 10" JL audio & Macintosh component speakers, running from an a/d/s P850 amp. Make sure installer is the highest quality you can find. You definatly get what you pay for. I had a horrible time with engine noise. In fact spent over $800 in labor to track down mistatkes made by another shop. BMW's are very "loud" when it comes to electrical noise. Perfect example is where they put the stock radio compnents