I've tried lots of ways to improve the rear brake centre hub (hammerite, STP brake paint etc) but I think the extra heat generated on track burns it of and they always end up rusty and looking sh*t.
Recently got a new set of drilled rear disks and someone suggested using BBQ paint, seems a bit weird but logical as its good for 425 C and happend to be the same colour as the BBS wheels
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Time will tell, also good for cooking sausages.