Here's a mod that has been gaining popularity due to all of the portable music players available today. When one wants to jam out to there MP3s in the car, they usually look to the RF transmitter solution. There are plenty available. Unfortunately, some of their specs are hard to find. It is my understanding that most do not work well in the city. From what I've read, the ones that can be manually tuned are the best.
So, I picked up this thing.

The results of the first run where typical. The main issues were static, hiss and distortion. I performed the notorious antenna extension mod. This did extend the range quite a bit. But, low end sounds were full of static, I could still hear a lot of distortion and the hiss was still present.

Then, I remembered I had this old thing. I picked it up in the late 90's and never really used it. Well, I did use it to overpower the lite rock station at the pizza shop in order to blast Christmas techno. To accomplish this, my transmitter had to be right next to the radio's receiver antenna.

I found some interesting info about my transmitter. Later versions of this unit had been modified from the original design in order to limit this unit's broadcasting ability. I assume this had something to do with a violation of FCC regulations. Pictured above is the evil limiting resistor.

With the resistor out of the way, you can see blatant trace cutting.

A small wire lead was all it took to complete the REPAIR. While I was at it, I replaced the original antenna with 3 feet of small gauge wire.

The results: My old Rat Shack transmitter completely spanked the competition. As soon as I turned it on, it claimed complete domination of the 88.9 frequency. The radio became completely silent. So I hooked up my juice box and played an MP3. The sound was loud and very clear. The bass was solid and distortion was nil. I could detect slight distortion if I maxed out the volume on the juice box. I moved the transmitter about the cabin and had minimal signal interference . I haven't tested the range, but I'm sure it's decent. So, if you're listening to your radio, and the music suddenly switches over to techno, look to see if there is a dark mustang nearby. If so, I apologize. I'm just passing through.