I'm not real sure how much.
Pro5 is selling his in the forsale forums, he stated NEW OEM price is around $800 USD.
I was thinking somewhere around 200, 225 with the moonroof deflector. I could be convinced to lower the price if you were willing to send me all the parts you took off your car.
Here's the deal on the install.
The forward/backward running rail (runs the length of the car) is held on by 4 bolts that go through the roof (you will have to remove the headliner). The two black trim strips that you have in place of the roof rack SHOULD be held on by sticky tape (but I'm not real sure). If you remove those, remove the headliner, you SHOULD have the 5 holes to push the rail through. Then you just tighten down the nuts, put the headliner back in, and you should be done.
I believe there was another Canadian that installed the American Roof racks, you may want to get in touch with him/her and get more information (could you pass it along to us if you do?)