Yup, I had one in my Trophy.
Along with the wiper stalk, I think it's the other "must" modification/addition.
If you do a search for tunepoint and my username, you should get the info you need.
Here we are: viewtopic.php?f=2&t=2639&p=60508&hilit=tunepoint#p60508
All I used was a drill to go through the piece of detachable plastic in the back of the glovebox and some twist ties for the cable. I'm about as useless as they come in regards to DIY and I found it well easy.
the tunepoint i had caused the head unit to fail totally, i had to have it changed under warranty, i sold the tunepoint on and didnt try to hook it up again, shame as it seemed like a great bit of kit...some guy over on CS called "denty" used to sell them all the time for £70 new if i remember.