Hi, I've got the chorous sound system in my car and the speakers are only in the front door. I'm used to at least having symphony sound system and this one drives me mad !! what can I do to improve the system? I know I can change the system to symphony or rns-e and rewire rear doors but it's too much money and too much work. Are there any cheaper modifications that would improve the sound quality? if I change just the speakers in the front door for something decent will this improve the sound a lot or is the headunit so restrictive?