Alpine KTP 445u = perfect upgrade for factory radio amplifier. Only problem is now i will need new speakers too because the stock ones distort easily now, couldn't really get then to distort with the factory radio. I used to run +6 to +8 bass and treble. Now maybe +2 bass and neutral mid/treble. A lot of the boominess is gone too with a similar sound to my ear and ear splitting volumes.
Volume level 6 now is equivalent to 20 before and 25 is pretty much too loud.