Still doesn't seem to be much information on these...
My brother has a set of the RS709 in his wrx and has been loving them - pretty similar to the project mu HC+ but better initial bite and seems better life.
I have just put a set of the SB511 in my r32 in place of some QFM comp 9's and heading down to Marulan in the morning so will give some feedback (can safely say they are much less noisy so far)