Chase Bays Thermostatic Oil Sandwich Plate M20x1.5 Most Subaru Models

Great product would recommend

You will need additional things for this to fit a Subaru. The flat design will not clear the timing cover of an EJ255. If used in conjunction with a water to oil cooler the product hits the exhaust manifold.

Its a beautiful product. The thermostatic valve is always open to warm the oil in the cooler, a nice design.

Doesn't fit a EJ20/EJ25.
Are most Subaru engines FA? Does this even fit the FA? I don't know.

What is terrible it that it doesn't fit without (1) cutting your timing cover, (2) keeping the water to oil cooler, or (3) buying a spacer.
Option 1 exposes your timing belt to dirt and problems.
Option 2 heats up the oil you just spent a lot of money to cool.
Option 3 requires stacking multiple products by different manufacturers, and hoping they all continue to produce replacement seals when the rubber seals inevitably go bad.

If you have to purchase other things to make it fit, it doesn't fit. The Roger Clark Motorsport Oil sandwich plate is a great example of a product that fits.