I heard the Tempest on a 90db (true measurement) MTM style speaker rated 4ohm nominal and it did very nicely. There is one here for sale about $1,450. I am not a Rogueophile but I was not aware of Magnum upgrades for the integrated stuff as Chelillingworth talked about but he is usually on top of this stuff (don't ya love it when the discussion goes to passive components and transformers instead of brand names.) Anyway, I know they have a Magnum Tempest amp with upgrades available. I have had a little experience w/ Jolida through a friend and at least with their amps the stock tubes are almost throw-aways if you ask me. Maybe just a bad exprience.
Sincerely, I remain