I´ve got a new sun roof in the garage (still in the box) and an XJ fun truck, that could probably use an emergancy exit, if I ever lay it on it´s side.
Look at the wifes XJ (that low speed rolled) and see the A pillers folded back, way to close to the headrests.
And say to myself, not putting in the sun roof, without a roll cage.
I´ve put a sun roof in a couple of PU´s, not real hard. Getting the headliner just right, isn´t easy. Masking tape and a sheet metal nibbler, make a pretty clean installation. Used an OEM quality mastic sealer (same stuff they use for the rain gutters and many of the body joints OEM). Most sunroofs, leak at sometime or another, even the factory installed units.