My TR6 uses a Mocal spin-on oil filter adapter with thermostatic control. The Adapter accepts the following filters for an early '90's Ford Escort:
Originally I had installed a Mocal 13 row cooler, however, I replaced it with a Perma-cool 201 three tube cooler to increase the heat transfer and decrease the pressure drop. The net result was an increase of a few psi and, hopefully, cooler oil.