Hi Richard, thank you for your helpful comments. I would be very dissapointed indeed if I had just purchased an SIA 025 for £18,500 new to find it was not an improvement over my SS-010 for sale at £3995! What I can say having listened to the SS-010 side by side with the current RI-100 is that the SS-010 does improve on the RI-100 offering greater refinement and naturalness to the sound particularly when operating in Class A mode which the RI-100 does not offer. You would however expect this to be the case seeing as the SS-010 is part of the Signature range, a level up from the Reference range that the RI-100 falls within (I think i'be got the names of the ranges the right way round but forgive me if not!). The only area the RI-100 surpassed the SS-010 was in terms of outright slam courtesy of its 300 watts on tap however I would say the SS-010 also has bags of power in reserve and there would be few speakers it could not drive fully.