I've used these brakes for 7 years on my R32 (although they are 355mm 6 pot fronts) and have been through a few rotors. There are $750 a pair, which is pretty good value. The next real option is to go to Harrop and pay ~$1,000 each. They'll last longer however I don't think the extra life makes up for the cost based on my experience.
Looking at your front rotors in your build thread, they don't look like BMAX originals as BMAX are all 36 vane. Did you buy the package new?
I would confirm the PCD with Sebastian at Ark Design and go from there. ALCON and AP would also be other options if you really wanted to go with other options however I'm unsure of the cost.