I remember what a ground breaking preamp the SP-10 was compared to the then current SP-6b,6c,6e and SP-8. There was really no comparison. The SP-10 just did everything spectacularly better. So I would assume the anniversary addition will do the same to the REF 3 and REF 5. If I only had the cash, I'd purchase one in a second!
ARC Reference Anniversary preamp in 2011