Hi there:
As a very happy owner of Sapphire XL's, and someone who has reviewed them with a lot of different amplifiers, I can definitely say that thanks to the very tube freindly crossover in these speakers, they will live happily ever after with a 30-40 watt tube amplifier.
However, this looks like a somewhat odd creation that someone built themselves, so beware. I'ts like a hot rod that had a whole bunch of modifications done to: If this ever breaks, you could have a heck of a time getting it fixed! And there is no resale value on u-build em gear, so keep that in mind as well.
If you want to go the tube route with these speakers, consider one of the Prima Luna power amps, like the Prologue 5, which is about 1400. This will be money well spent on a NEW amplifier with a warranty, that so far has had no field failures in two years.
If this is a bit out of budget, consider an VT 60 from ARC, you can pick one of these up for about 900 on the used market, or perhaps an MV 50 or MV 52 from Conrad Johnson. Here you are looking at spending 5-700. Though used, both of these are from reputable companies that you can still get service and support.
When I first met Mike, the XL's were playing through a Prima Luna amp and they sounded great.
But I can tell you that these are good enough speakers, that should you decide to upgrade your
system a few levels in the years to come, the XL's have enough resolution that the speakers
will probably be the last thing you need to upgrade!
Good luck...
