I did the exact same thing on my SVT!!

This is quite a bit more scary to do than the Mystique light though. You have to cut out the frame for the mystique light to get the light to fit. Then you have to trim the bezel so that it fits flush with the headliner. You also have to cut a much larger hole in the headliner

In other words, measure once, twice. Double-check those measurements, and then measure again.

You only get one shot! A new headliner ain't cheap!
The final product is far classier than the mystique light as Brake-buster's picture illustrates. I got my light and bezel off of a wrecked GL (not sure what year but I'm sure they all had 'em) with no sunroof. I bought the mystique light and when I got it, I says to myself..."self, there is no way in hell that you are putting that ugly thing into your headliner!!" I plan on using it for the passenger foot-well. I'm gonna hide them under the seat because it seams so dark down there now that I have the rear dome light that Furd SHOULD HAVE PUT IN THESE CARS!!

Looks like a factory install

Do it! You wont regret!