hey i know its kinda old, but ill pipe in.
The Cleansweep unit is a unit that will take all your speaker level inputs from your stock headunit (only up to 4 channels) and will un-equalize the signal, and put out a much cleaner and flat signal to go to aftermarket amplifiers.
If your going to upgrade youre speakers I would definately suggest getting either a Cleansweep unit or the (better IMO) Rockford Fosgate 3Sixty.1 or .2. The stock radios always will be equalized before hand to help counteract the quality deficiencies in the equipment, so certain freq will be enhanced and others decreased. this helps stock system sound better, but really wouldnt help with aftermarket speakers or espeically could hurt you if youre putting in amplifiers to speakers of any kind.
If you are just wanting to throw some better speakers in there, and want to retain all your steering wheel controls, then the Cleansweep would be fine for you, but if you are also wanting to put a subwoofer, then the 3sixty is by far the superior unit, the main drawback is that you need a palm to tune the 3sixty, but nonetheless it is a AmAZING unit. offers the quality of the highest end radios with the look and useability of all your stock radio equipment. Hopefully this helped those people with any questions about their OEM integration options.