Here is what I did, chuck the door & factory sub (just put them in a box and store them in your basement, they will sound better there ).
Keep the head unit add a line level converter (PAC work well) and a four channel amp. Make sure the amp is small, I remounted my amp in the factory sub location of the passenger foot well. Now here is the important part that makes the biggest change, use a good set of 8" component separates speakers in the door locations, this will require some mods, but nothing to difficult. The key is to make sure the drivers are sealed to the door panel to make sure no air can move from the front of the speaker to the back. I sealed mine with a non-porous high density foam.
Hook the front left and right channels from the amp to the door speakers, then bridge the two rear channels and run that to the center channel speaker in the compartment by the center console. Set the input level on rear channels of the amp considerable lower than the fronts, and set the entire system for your max listening level = to volume knob of the head unit pointing at 1:00.
If you need more detail or a parts list email me, I have been putting simple stealth systems in my cars for years, and you dont need 12" woofers and 14 speakers or 2000 watts to make have an excellent sound for your excellent car. I will send you pictures and detailed instructions if you need them.
The difference from stock is so noticable that many people cant believe I do not have a Sub and everyone asks where are all the speakers. I tell them it is not hard to hide three speakers!
