Most people seem to recommend the PWR radiator, but say it can be a bit fiddly to fit. (doesn't concern me much as I have plenty of tools and access to machining equipment)
Most people on miata.net seem to recommend the Koyo 37mm radiator, which is significantly cheaper in the US.
Seeing as the PWR ones are made here in aus they both work out very similar in price landed at my door.
Which would people recommend, and why?
