I am not sure which cooler you have because I can not find #70265. What size is the cooler??
I use a #70274 (11"x11"x1 1/2") cooler for my engine oil which is the largest cooler (air/oil) Long makes which is rated for 200 psig. I use a thermostat (B&M #70259) only because of the air temperature difference between winter and summer in the Phoenix area. I use the largest cooler for summer operation, and include the thermostat for winter operation. If I did not have the thermostat, my oil would not be hot enough to evaporate off any moisture buildup in the oil during the winter.
Every application is different. I am assuming your cooler is the smaller one offered (11"x8"x1 1/2") because you summer air temperature is much lower. If you park the car during the winter, you should not need a thermostat.
By the way, I am not using the "Turbo Saver" filter setup, I am using a Biggy Filter for the engine, and a separate filter for the turbo.
Deep Enough
Donald McMullin