I have had an SP9 mkIII in my system now for about 6 years.
All my componets except(of course) the turntable is from
Audio Research. I'm using Audio Magic Sorceror interconnects
and Kimber speaker cable. Speakers are the Dunlavy SCV(s).
I have done a fair amount of tweeking with the preamp and have found that the unit is capable of really very excellent performance under best conditions. Some the tweeks include using isolation devices under the unit resting on a 2" thick granite base resting on sorbothane type pods. I have also found the unit sounds slightly more detailed with the top grill off. Using the Densen Demag CD every 3-4 days also makes a difference.
I've come to the conclusion that system synergy and attention to detail probably has allot more to do with satisfying results than adding the new 'product of the month'.