http://www.e90post.com/forums/showthread.php?t=641323
Ignoring the eq on the head unit is a big mistake.
Driving aftermarket speaker with the head unit is a big mistake
they barely have enough power for the speakers that are in there now.
Leaving the rears on the head unit should be OK
That's a 4 year old post you are looking at there are better solutions
now but there not cheap.