Like many others, I wasn't very impressed with the sound of the factory stereo. As well, I'm more interested in racing the car than having a touring toy. So in my quest for weight reduction and the need to have tunes getting to and from events...plus the need for a bit of data acquisition via iPhone.
So here's what I did:
After removing all of the old stereo stuff, I mounted a Rockford Fosgate 4X75 amp with RCA inputs in the trunk and ran the RCA cable/headphone plug up to the cabin. I've mounted a very secure iPhone cradle under the dash where the center console used to be, and moved the storage shelf into the radio slot. The original dash and door speakers were swapped for appropriate sized Infinity Kappa units and wired to the amp with the factory wires. Using the iPhone, I've either got my IPod functions, or I can get radio through I-Heart-Radio or a similar app. The amp had separate gain controls for front and rear speakers, so I was able to bias a bit more to the door speakers. No balance control, but who cares. Volume is controlled through the phone. The cradle sits just far enough from the shifter that it's out of the way, but within easy reach.
The sound, uh...rocks!