Someone asked earlier in the thread - A MSP wheel/tire combo with 6kmiles on the tire weight about 42 pounds as weighed on my professionally calibrated six-dollar Ikea bathroom scale (hey - close enough).
You can check TireRack.com for the tire weight and subtract it for the wheel weight. There are definitely lighter wheels available, again TireRack.com has 'em and has weights listed (Kosei 17" for 16.5lb each, various Kazaras at ~ 18.1lb, BBS at 18.5lb, etc.).
Be sure to at least sand down and seal that area with clear to prevent the aluminum oxidizing underneath the finish and and flaking it off around the scrape. Getting it fixed may not be a big deal, there are wheel repair firms out there (check the back of Car&Driver, Road&Track, or internet). Don't know about color matching though.
Good luck - sorry to hear about the scrape.