[rattlsnak]

As far as the weight, they are relatively light, but I'm not sure as they have tires on them, but I found this thread where it looks like they weigh @ 18- 20lbs.

Forgeline RS Comp's 17x9 - Bimmerforums - The Ultimate BMW Forum

and this says @ 18.75 lbs.:

Custom Rims - Buxton Motorsports, Inc., Authorized Panoz dealer and Nationwide Dealer of Pre-owned European Automobiles.

I can measure the offsets tomorrow, but they are made to fit under normal Carrera or SC bodied cars.