.
I've read UNIbrace's tester's report/opinion about the RB but I'm not sure about what it would add being worthwhile for a fast road car if you already have the XB and UB. Probably much more benefit if doing trackdays.
I have to admit that I wasn't at all sure about the XB and UB until I tried them but does the RB add something you can really feel? The jury is still out for me and I need more evidence.