Neither my CVH running around 270bhp @ 32psi nor my ZT running around 300bhp @ 22psi ran even slightly hot in the Cabby.... and by hot I mean over 115 degree's after sustained periods of WOT with an ambient of 25 degree's.

I didn't run water cooling to the turbo on either and on the ZT I had no oil cooler either... well, it was there but I never got round to plumbing it in! lol
Maybe these had an effect?! But my bumper did allow for very good airflow to the IC and rad.