Also, methinks you can buy Kenwood ones for 300 these days, so why not just go this way for the sake of cost and warranty?.
Another thought, my girlfriend is going to buy a portable mini-disc player and they have inputs to plug into the car CD players. For example, my CD player (all $300 of it) has RCA inputs on it, so I just plug in the mini-disc player and then I can listen to 320mins (changes depending on brand and size) of MP3's. The good thing about this is that you have a portable MP3 player and also the MP3'S in the car when you want them.
I know Sony has one we are looking at...the MD80 or 90 for about 400. That price is from Harvey Norman, which means much cheaper anywhere else.