Like a lot of people, I upgraded my stereo over the course of several years.  Since I'm a do-it-myself kind of guy, I spent a lot of time, saved a little money, and got the satisfaction of knowing everything was installed "my way".

Phase 1 -

Installed decent door speakers, external amplifier, and bass shakers, while retaining the stock head unit.  Better speakers and an amp made a BIG difference.

See more pictures here.

 
 

 

   
Phase 2 - Changed to a Sony MP450 head unit with MP3 capability, and added S2kman's DCU to keep the stock dash switches working.  When the DCU crapped out, I decided to make my own interface, the now nearly-world-famous DCI.

Sorry, no pics of the HU, but you can see info on the interface that allows you to use the stock dash controls with most after-market head units.  Go here.

 

   
 

 

   
Phase 3 - Added a 10" subwoofer in the passenger foot well, powered by a Blaupunkt plastic amp.  I managed to fit a 5.5" deep sub and lost less than 3" of leg room.  Not an easy mod, but since I'm a trunk-space-a-holic, I had no choice but put the sub in the cabin.

See the whole gruesome story here.