First...Welcome!
Besides the roof, be aware that the midgate (glass) and endgate (which can open both vertically / horizontally) tend to have problems as well. Actually, they tend to have issues much more frequently than the roof (probably only because the roof panel isn't retracted nearly as much as the mid- / endgates are).
If you run into another one of these in a local junkyard or on Craigslist - give serious thought to buying it & saving it for a parts car, if you have the room. The XUV has many 'unique' parts to it (especially the SLEs, which have the cloth-style interior).
If you can't house an entire parts car, bookmark 'XUV' in your local CL and search it every so often -
everything on the body / interior from the rear doors back is XUV-specific, even the taillights & rear wiper. If you ever do a side-by-side comparo of an XL with an XUV (even online), the differences will be more apparent.
Give some thought to leaving the midgate in a permanent 'up' or 'down' position - or, don't fret if it ever gets stuck in the 'up', when you wanted it 'down' (it won't fold down unless the glass is retracted into the gate - or, to be more precise, the CAN bus *recognizes* it to be retracted). Same for the endgate, which has additional issues, since it can open two different ways.
Those XUV modules are worth gold. Get some to have as spares.
eBay is your XUV's new BFF (I've gotten lots of used parts there for my XL, way cheaper than elsewhere.) Car-part.com can net some goodies (they're nationwide), but you'll pay more (it's a nationwide junkyard / salvage network.) They're good for body parts & major assemblies (although if you have to replace engine / trans at this point, you may decide to just cut your losses, even though those parts are shared across the platforms.)
A service manual (with the XUV supplements, where applicable) will save you & your mech a lot of time / frustration. You can download them from Mooseman's link in his sig.
It was only sold for 2 years - and in such few numbers, the main parts supplier almost went under b/c GM assured them it would sell like hotcakes, and the supplier sunk a lot of capital into producing the parts - only to see GM cancel delivery of most of the anticipated shipments, as sales never materialized.
The other thing that hurts you, parts-wise, is that it was a GMC exclusive. A real white elephant, as it were.
Good luck, and don't be a stranger. Unlike many here, I liked the XUV, and wanted one when I was looking for my XL - until I found out the 'special' issues they presented. I loved the concept, and even remember the ad copy from when it was introduced back in '04. I just don't want to be constantly worrying about panels going back into place as needed. And the cloth seats are just g*d-awful ugly (sorry if I offended, but there's no gentle way to say it).
If you have leather - count your blessings (and enjoy the seat heaters!
On edit: Oops...I see you have the SLE. But - you DO have the best exterior color!
(GM later renamed it 'Spiral Gray Metallic', if you're in the market for a touch-up pen / spray can).