I'll be in Tokyo at the weekend, and might look for one of these, but, based on the description (and cross section diagram) on their website I'm unsure of a few points.
http://www.trasko-usa.com/faq/faq.htm
1. How often is it likely to be in their "bypass mode"? (I'll call it semi-bypass. I'm using bypass here in the sense that the flow bypasses the restrictive filter, as happens in a conventional filter when its very cold)
They say it goes into semi-bypass at between 8 and 16 psi at the internal relief valve.
That's presumably a pressure differential across the relief valve, rather than an absolute pressure, since if it were an absolute pressure it'd be in semi-bypass all the time (but then maybe it is.)
Assuming it is a differential, I don't know how often that's likely to happen. I suppose it'll depend on the downstream resistance to flow in bearings etc.
2. How well is it likely to work in semi-bypass? They claim retention of 8-10 micron particles, based on a stainless steel mesh with holes that big, BUT
(a) The mesh doesn't seem to have a lot of area. (no pleats)
(b) There is presumably no depth-filtration effect from the mesh, as there is with a conventional paper filter.
This makes it seem likely to clog pretty quickly.
3. What happens if/when the mesh clogs? Is there a real/full bypass mode? (I'd hope/assume so. I THINK most cars have this external to the filter, otherwise you'd be reliant on flow through the paper depth media which in this filter is probably quite restrictive, and the engine might die.