Just got my wheels from my Audi B7 A4 Avant track day friend. They come with plastic hub rings - 72.5mm to 57.1mm. Right size for the wheels and my B7 A4 hubs (research indicates).

However, they are plastic so under track day conditions we could/will see melting?

So the solution is get a set of aluminum hub rings?

Sidebar question - wheels also came with a set of lug bolts at right length for them. Likely not pricey ones but any reason not to use them?

just bring a putty knife to break them loose from the hub....

used plastic rings several times at the track.

Gary recommended aluminum rings for track use, but I think the plastic ones will suffice. The only problem I've had with the plastic rings is that they sometimes snap when removing wheels, prying them off, etc. So either get 4 aluminum rings, or 5-6 plastic rings so you've got extras.

or so... As usual, your mileage may vary.