Shrouding the radiator makes a huge differnce. I have the stock radiator (83GTI) shrouded on all 4 sides with a slightly lower thermostat and a 1/8" hole drilled in it for bleeding the air out. With the new motor before I put the oil cooler on I had temps at exactly 190 never went over even a mm on the gauge and the oil temps were pretty high I also don't run a fan so you get much better flow through the radiator.