The head unit supplies an unamplified signal. Any amplifier aftermarket or the stock amp will work with the head unit to amplify the signal to run the speakers.

Sell 'em up on ebay as a package deal. I got $187.50 for mine.

1999 Ford Contour SVT #900/2760 (SOLD) 2005 Mazda 6s 2003.5 Mazdaspeed Protege 1998 Ford Ranger 4x4