Hi,
My 99 t/a convertible has the parts below. It sounds fine but bass starts to distort at the top. Will a better amp and/or speakers help me? If so, can you suggest something? Of course I will keep my expectations realistic being there is no roof. Ty.

Pioneer double din head unit.

Pioneer GM-4604 480w amp

Pioneer TS-A6966 A Series 6" X 9" 420W

4X6 standard Kickers in the doors.