I have just replaced my front door speakers with some 6.5" 8ohm Vifa woofers that you buy for kit speakers, They sound alot better than the stock Mc'intosh ones I think, Now I just have to do my rear doors probably just get some good quality coaxials as you don't need component speakers behind you, Sub wise I have a 10" connected to the plug for the factory sub in the boot... the system sounds pretty decent for a factory head unit and amp I wouldn't change a thing.