And even worse, the old wheel studs are not even long enough for the spacers, The Nyloc's arn't touching the thread.

I think you'll find they are steel and the old studs are in fact being used to hold the wheel on and a shorter stud has been fitted to the hub.

Still don't like the look of the non engaging nylon.

Then how could it change the PCD?

Looks very dodgy to me. Nothing wrong with alloy spacers. In the 4WD world you can get up to 3" alloy spacers. They bolt on by the original wheel studs and have new studs with them. But i was running 1.5" and they only just cleared the nut on the original stud and 1.5" is a huge increase of track on a datto!

What I meant is that the standard studs were pressed into the adapter plate and a shorter stud was put in the original hub locations.

I don't see how these are any worse than any other adapter out there apart from the non locking nylock nuts. I'd like to see a countersink put in the adapter and some tapered nuts though.

To get those nylon nuts to bolt up completely just machine some larger diameter holes about 3-5mm deeper but get the depth perfect on each one.