I had the itrip and it would always fade out; I always ended up holding the ipod in my hand. I installed the USA-spec ipod interface. I forgot how much sound quality is lost through a FM transmitter. You would need to disconnect your disc changer. I would prefer my ipod to six disc changer though.
Keep in mind that you can buy a FM Modulator which plugs directly into your stereos antenna jack. Those never fade out. You would need to tap into the cigarette lighter type thing for power (easy to do).
For the interface i have, heres some pros and cons.

Pros - no external power needed to supply the interface, interface charges ipod, disc 1 through 5 are each a different playlist, disc 6 is everything on your ipod, random feature, it's super easy to install and no wires showing, and best of all is that you don't lose any sound quality.

Cons - playlists have to be named HONDA1 ,HONDA2, etc, you cant see song titles, its hard to find a specific song (solution - unplug ipod, select song as you normally would, pause song, then plug it back in. it will start where you paused it [hope that makes sense]), you can't skip back to begining of a song in random mode ("fast rewind" only), it costs around $100, and the worst thing is that mine will randomly stop in the middle of a song and skip to the next song (kinda sucks when you into a song)

Hope this is some help to you.