The Alpine iDA-X100 hooks up real well with the I-pod, that's the unit I put in my Xfire. Mine didn't use the trim ring, just pulled the stock unit out, wired up the new wire harness, and plugged into place. Then they came out with the Marine unit, I'll use it for the wife's Roadster so it'll match her dash.
Here is a pic of mine in the dash. I liked it better after I did the dash kit, the black actually blended better than the stock or Marine unit would have.