John,
you're welcome.
My opinion: Keep this classic (and actually rare) car in original condition. So I'd go for UFO rotors. Some guys over here upgrade their front brakes with the HP2 from the Audi A8 (D2). But that needs a bit more work to be done. The HP2 calipers don't fit to the HP1 (UFO) mounting bores. The hubs need to be changed. Due, the complete front struts should be exchanged. But, to my knowledge, even then a few further adaptations needed to be done.
The rear brakes don't need an upgrade in any way.

I have found out your location is the US (Dinam BMW). So I don't think you really need a break upgrade. The UFO brake is not so suitable for permanent high speed racing on the German Autobahn. Then they wear pretty fast and the UFOs are really expansive. Moreover, the HP2 has a bit more power.
But driving US Highways should never stretch the UFOs to their limits and they will surely last much longer.

Beste Grüße
Tim