There was a guy on one of the FiST forums that installed the DHM intercooler with crash bar and I think during his YouTube video he he say 20-40f increase in coolant temps during hard driving then before the install. As a result of reduced air flow to the radiator he installed the Mishimoto radiator which brought temps just below stock levels. Yes the DHM intercooler gave really low Delta temps for the intercooler but the coolant system paid the price. Again the difference between bar and plate (DHM) and tube and fin (mountune and mishimoto).
I am hoping that by the time I go to anything which requires the DHM Race IC/crash bar setup (IF ever), someone else BESIDES Mishi has a top line radiator out for these cars, which has the potential to drop the coolant temps even more yet. (I now REFUSE to pay Mishi's price for a Sino made radiator! ).