Just a note, KNS Brakes has DBA rotor rings for $295 each. With the replacement hardware and shipping you're looking at ~$350 each. I've been dealing with KNS for probably 15 years or more - they're good folks, car enthusiasts themselves, and very knowledgeable. (I've actually met the owner at track events on a few occasions.)

I put V2 brakes on my V1 back in 2012, and since I track the car (well, used to track the car) I always had 3 or 4 sets of rotors on hand. It used to be that the cheapest thing to do was just buy new, complete OEM Brembo rotors, usually from Rock Auto. But over the past couple/few years, the OEM rotor prices have really jumped - in the past I'd gotten them as cheaply as $300 each, now they're about $510 each on Rock Auto. MSRP from a dealer is going to be like $800 each or something ridiculous like that. Those sort of prices make the replacement rings the way to go.

I ordered a pair from KNS a couple weeks ago, and figured I'd give a heads up to others, since brakes are one of the more expensive routine maintenance items on these cars. Here's one of the DBA rings, a packet of hardware, and my used modified center hat ready to assemble: