Wheel spacers will increase the stress on the studs. I prefer not to run them. But, lots of people do without any problems. It also depends on the wheel width, offset, Etc. Wider wheels, higher horsepower and age are all problematic with these older cars. If you are only running a 1/2" spacer it is probably ok, but don't quote me. You are the one that needs to make the descision when making modifications. It is likely that Moroso's lawyers require the warning.