Hi Loren,

I have a few of the little FM transmitter MP3 players that take a USB drive
or memory card.  They work pretty well when you are in rural areas that have
relatively few radio stations, but when you get near a city it can be tough
to find a channel that will work well (at least this is the case in the
northeast).  I have also noticed that the sound quality of these little guys
isn't quite what I am looking for in most cases even when I have a good
signal.

I think the issue with FM Transmitters these days is that the FCC regulates
the strength of transmitting devices pretty closely.  A few years back many
satellite radios used an FM transmitter to connect the signal from the
satellite unit to the vehicles stereo.   Many of these transmitters could
broadcast for up to 150' or so over the chosen frequency.  This was great
when we wanted to listen to satellite radio on the jobsite thru whatever
radio we had on hand, but not so great when I was cruising down the highway
and someone else's music started coming in over my speakers since we were
using the same broadcast frequency.

Nowadays most satellite radios use an FM Modulator instead of a FM
transmitter.  An FM Modulator installs inline between your antenna and your
head unit and completely takes over the frequency you choose when switched
on.  This results in way better sound quality and eliminates the need to
have to hunt for a clear channel in urban areas.

I recently installed an Audiovox FM100A FM Modulator in my '87 Wolfsburg and
couldn't be happier with the results.  This unit basically functions as an
auxiliary input for your radio and allows you to use any standard MP3 player
or other device with a standard headphone jack (cell phone, laptop etc).

Here is a link to the Audiovox unit, there are also models from Scosche and
Boss Audio available for about the same price.

http://www.amazon.com/Audiovox-FM100A-Modulator-Isolation-Transformer/dp/B00
01KO7UI/ref=sr_1_5?ie=UTF8&qid=1287174322&sr=8-5

Hope that helps,
Jay Brown
'85 Zetec Westfalia
'87 Zetec Wolfsburg