Wheel Spacers and Adaptors

Hey guys, I know we have beaten the wheel topics to death, but I havent heard much talk about adapters for wheels. I was wondering if there are spacers or adapters for wheels that have a higher offset (stick out less) than what the factory wheels call for, and if so, what have people experienced with using them.

From what i've heard they are bad for your car, but i never seen a case of it. Wheels I was lookin at for my car wont fit it, so i was checkin these guys out. They look pretty sturdy. They'll make an adapter to fit any wheels to your ride.