Nodiak,
IMO, your best bet is a ClariT without volume control (use your own tube preamp) with Black Gate caps upgrade. My a little overkilled monoblocks are giving more juice and db (loudness) that I ever need on my 90 db speakers, and I are not even using an active preamp.
No I haven't heard the stock SI to tell how different a jump from it to the ClariT in terms of subjective power. However, as I posted elsewhere, going from a stereo ClariT with volume control and stock caps to monoblocks without volume pot and with BG caps is one big dramatic leap in perceived power AND fidelity, considering that the stock ClariT is already a very strong musical performer.
The ClariT doesn't exhibit the noise or hum that several stock SI customers talked about. In fact it (ClariT) is about one of quietest amps, only second to FirstWatt F1, which however can be on the verge of sounding sterile. Bottom line is, a modded Tripath is likely to give higher fidelity, less to minimum noise, AND more power due to its better juice (SLA battery) and simple cleaner more direct electronics.