Best DIY SET int/power amp?

I have this urge to hear an SET set-up in a small second system, but dont want to be dissatisfied with a novice, 8 WPC system that I'll have to upgrade after a short while, so am looking for suggestions for at least a 15 WPC system that I can build. Room size 12 X 12 X 10, listen to mostly classical, medium volume. Currently have Totem Sig 1, 87 db, 4 ohms. Budget about $1500-$2000 for amp.
Current small system: Jolida 502B level 1 mod with NOS tubes, Cairn-Fogg V2.0 with upsampler card, Acoustic Zen Double barrel biwire S/C, Empress i/cs, totems, VH P/Cs.
Ideally, an int amp, but if not possible, then a power amp.
Will I have to trade the speakers for single-drivers of 95 db or thereabouts?
Appreciate any input, as always.