How dop I make the old 1200 Panasonic radio sound better

[machz54]

After changing and trying all types of speakers I decided that the panasonic was just a sub standard unit and decided to replace it ,I did some looking around and came up with a JVC KD R218 unit it has CD am fm and Aux input rated at 20watt rms,
To install unit I removed all of the stuff used for the old radio mounting including wiring and amp,new unit fits quite nice and sounds great,not much louder than old one but way better sound ,also comes with full function wireless remote that velcro,s nicely to drivers side,bought unit at future shop on sale $99,dont miss old one at all,will try to post pics if anyone interested