The Greddy one DOES have a thermostat?... SPECIFICATIONS: Application: Engine Side Type: E (Standard Oil Cooler, Non-Relocation Type, Internal Thermostat) Union: AN8, AN10, AN12 Center Bolt: 3/4x16UNF, M20xP1.5
A DIY cooler set up will cost less than or around $400.
$140 for Greddy Sandwich plate $150-180 for 19 row Mocal cooler (I bought Mocal because its said that every cooler has been tested to hold 180psi before leaving factory) $10 x 4 -10AN fittings from Torques UK
3m of black nylon braided hoses
The Greddy thermostat opens up fully at 80 degrees and I think slightly open before that. It is also been tried and tested by many and proven to be very good lol