Mishimoto Thermostatic Sandwich plate (MMOP-SPT), suits 2ZZ cars and may suit others - but not sure. It has the original thermostat in it (84C, I think) and comes with custom adapters to suit the factory oil cooler lines in the Elise/Exige with twin oil coolers
Also included is a remote t-piece for the 1/8npt sensor port. You can either use this to fit two oil sensors into the one port, or as I did just use it for relocating one to a more convenient location. (includes a 1/8npt blank in case you only use the one port).
£60 posted in the UK takes the lot.