ok, i have a vauxhall astra sport, iv just installed a Sony 4000watt amp with a JLB 2000watt subwoofer and a JLB 500watt subwoofer, plus iv upgraded the car door speakers to 2 600watt BOSS speakers (Rear Doors) and 2 700watt JLB speakers (front doors), my head unit is a BOSS system with more sub...