i'm gonna have to look for those wheels next time i go to a car show, and pick them apart..
a motorcycle wouldn't be too bad with just a spacer-- the axle is still solidly bolted in so if this spacer blew up, there might be a little slop, but the bike would be able to be safely stopped--yes, the disc brake might drag, and wear out a set of pads or tweak the alignment of the caliper, but nothing catastrophic 'should' happen--the wheel will stay bolted to the bike..
on a car, i don't like the idea of any spacer like that-- if that blows up, the lugs go loose, it stresses the lugs, bad things can happen with loose lug nuts..
my main problem with el is that it is dim. so if you ever park under bright lights, it is nearly impossible to see..
either way, once i figure out how they do it, i might have to build a set of self-righting center cap logo's just to mess with..