Umm, do a search on this thing guys.
It's a glorified LOC that is designed as a solution for cars with premium sound systems and integrated components (nav, steering wheel controls, blue tooth cell phone controls, etc) that won't work with aftermarket head units. Many premium systems don't put out a flat signal but instead optimize the signal for the factory speakers. Tuning such a system for use with aftermarket speakers and amps can be a nightmare.
The clean-sweep is basically an EQ for your head unit. It is not an EQ for your system. It basically make the frequency response of your head unit equal to an aftermarket unit. However, that doesn't mean that the sound quality is going to be on par.
The clean-sweep comes with it's own volume knob. You are instructed to set the factory system's volume at a specific level, configure the unit, and then never touch the factory volume again.
For the price they charge, I would not recommend it to any Mazda3 or Protege owners. You can get much better SQ from an aftermarket unit at a fraction of the price.