We installed the Custom Aduio Sound system with the same concerns you have. Ended up with the dual dash speaker and undercover rear speakes. They fit nicley under the seat. Didnt have to cut any panels which left a completly stock apperance. Plenty loud cruising with the top down. The best part is it's MP3 compatible. We have all our songs loaded on a small 4G flash drive that sits in the ash tray.
