The dealer had the sunroof installed by a shop in Toronto that's been doing sunroof installs for years. It's a brand-name sunroof with a warranty as long as the car's (could have gone for longer but it's a lease, so don't need it). The install looks like it was done at the factory. New headliner and sliding shade, finished inside nicer than the factory Subaru sunroof and a larger glass panel as well. They integrated the sunroof switch into the factory map light panel and the switch is illuminated. No leaks or any other problem, just over 2 years in now. I'd do it again, but it's pricey, so you have to really need a sunroof in a car to go for it.
The Impreza isn't really a wagon, just looks more like one than the 3 does because of the rear windows.