I've put my Quickie in front of the Stereomour and it's hard to say what it brings to the sound, if anything. The extra gain is nice to have, when playing records. At lower volumes I think I like it better without the Quickie. Volume matched I can barely tell the difference, though.
Passive in front of 2 Stereomours, Smash in front of the other one. I didn't need the extra gain until I got some MMG's, then I had to do the interconnect puzzle and dance to get everything connected so the Smash/Stereomour/MMG combo could play all the sources.