I have one on mine. Came with the car when I bought my ’05 M6 last year with 10k miles on it. There is one guarantee with every sunroof ever made by every manufacturer, it will at sometime leak, and often at an inopportune time and/or cost. And as has been said before, “once it’s cut it’s cut.” Personally, I would not have had the sun roof installed, had the car not come with it already. Just to not go through the headache of when, not if, water gets inside (smell, electrical issues, mold) and to retain structural integrity, especially if you are adding power or torque. If you have a need to spend money on your GTO, replace parts that are due for changeout or save it for getting your seats reupholstered, door moulding rubber, clutch, suspension, etc. There is a shopping list posted somewhere on this site that goes through a good chunk of this. My slave cylinder blew out the diaphragm recently at 17k miles, mostly from sitting and decay. Nevertheless, $2500 between parts from tick performance (tick/monster complete kit) and a man that backs his labor for install, just to not have to contest with the diaphragm problem again.Once it's cut its CUT!!!!!!! I'd like to know just how many 04-06 GTO owners have one?