I agree about the synergy between components, I think everything in the signal path makes a difference. The 25 ohm resistor I have shunted on both low and high frequency terminals, (Cornwall's) and the tinned copper wire from Duelund have made a huge difference in my love for this amp. I originally tried the 10 ohm resistors at Nelson's suggestion, but decided that was a little much and settled on 25 ohm.
I think with any amp you have to experiment with power cords, speaker wire, interconnects, 6922 tubes (Dodd) and in my case resistors to get the very best out of your amplifier. The SIT-3 is known to sound its best pushing a 4 ohm load.
My guess is that there are a lot of people that decide to try a new amp but never make the correct adjustments to make it sound its best. They never allow their forever amp a chance to shine, before they sell it someone else.
If you blinded folded audiophile friends that visit, they'd think they were listening to tubes.
ps. The Supratek preamp, and First Watt SIT 3 should wonderful together also.