[Bob Putnam]

I can't say about other cars' wheels, but on an ERA the wheels look exactly the same. Park takes a little extra material off the wheel's mounting surface to compensate for the thickness of the adapter. The adapter is also a little bit shorter so that it doesn't extend past the outside of the wheel/wing nut too much.

The primary disadvantages to the 5-pins are about 3 lbs extra at each wheel and the added complication and possible failure of the adapter.