What amp and speaker combo do you recommend and have tested working great - loud and clear!!!

I currently have the JBL GTO 638 Speakers with the stock amp and stock exhaust and they sound OK at 80 -90 mph with half helmet. For safety reasons I am starting to use my Schuberth C3 modular helmet with the chin bar and shield removed with Wiley X Airrage Sunglasses (I live in Florida 90 degree plus weather) and can hear OK but I want it louder please.

stevenolts