The stock premium sound system in my 89 SC has gone bad. The right side has no volumn. I think it's time for another system. Will another system fit right in? Do I have to change the amp and speakers also? I'm not sure what to do,where to go and what kind of system to get. I would like to stay around the $200 range -if possible. Anybody have a suggestion or what have you done that can be helpful. Thanks Rick