I paid $940 for my Sunroof (Hollandia-Webasto like dyanni's above), and it's an inside installation. Looks just like factory. I think if you shop around you'll find one for a reasonable price... it's well worth it and perhaps my favorite mod.

No problems with leaks whatsoever. If you have the exterior wind-visor (it cuts down on the noise), you do need to be careful parking on a hill nose down...it'll fill with water. Not a nice thing to find out opening the thing when it's full of water!

-- John