That price is exactly why I wasn't going to retain the UFOs. The pads are not cheap, either. When you can find them, here. Unfortunately, the UK market seems to have been quite limited wrt ufo equipped cars, and so sourcing service parts is not easy.
As I mentioned, the design itself is quite intriguing, and if it were cost effective and convenient, I would have retained them on 2 of my cars.

My third V8 has UFOs still, but the calipers need a strip and refurb. And pads.

85 WR quattro
90 V8 Silver, 91 V8 Black, 93 V8 Lago
93 100e quattro V6. Titan, i think