I have the TC XLT which has the walls covered w/ the grey skin. Its easy to take the rear speakers off - just lightly pop the inner circle and that exposes you to the screws (starbit).
I'm not sure of the quality of those speakers - seems like a big magnet w/ 35 watts. I was thinking of replacing them w/ better speakers but will prob install an amp instead to give the existing radio a boost.
Good luck.