When I was researching it, there was a beautiful alu machined piece of art from a small shop in Japan. Total CNC porn. I've been searching for that shop ever since I lost the link I ended up buying stock parts (Earl's) and machining them to suit the Copen. Hoses were supplied direct from Goodridge and made to measure. Sandwich plate was tapped for pressure sensors before and after the oil filter. I logged differential pressure via the Blitz SBC unit. It is an old practice. Differential pressure will climb as the filter media gets clogged. Once the filter is "blocked" - differential pressure drops to zero as the filter bypasses internally (spring loaded bypass).
