Anyone ever use these? They are hub centric and the two peices are machined to fit together.

Never seen these before but I think most people would advise street use only if using adapters of any kind. IMO

They do nicely made. but I would think that they would cost more than simply having the hubs correctly redrilled for 5 lugs. Are you looking for adapters or spacers?

I'd also agree that only for street use. If you want to use period correct Fuchs, you will change the offset considerably with these adapters. If you're using later wheels from 964, 993, Boxsters, etc., then they might work OK.

many race sanctioning bodies will not allow adapters

They look well built but they also look scary! I would not use them or any other adapter. I will admit that I used spacers on my 911 that bolted to the hub and had studs to mount the wheel to. I never trusted them. Sold my 911 and bought my 914.

I have a set. They are well made. The have a 1 million dollar insurance policy from the mnufacturer. Not cheap.

http://www.motorsport-tech.com/wheel_adapters.html

They would be for street only.They are expensive but still cheaper than the cost of long studs, machining, spacers, and new rear bearings.

they are concentric locating to each other , but the set in the picture is not hub centric to the hub or the wheel.

That is correct for the ones in the picture. But the ones that you order are hub centric and wheel centric. You can also order them lug centric to the car and wheel centric as well. That would take care of the front and back of the car. The ones pictured are lug centic to the car with a chevy pattern to the wheel. They came with some parts I aquired over the years.