there are other things that are wrong if you are overheating a disc that size from a single stop.
...1st, why do you think they are over heating? are they smoking? are they not stopping well at the end? the the brakes just "go away"?
...2nd, how thick is the rotor and what pad compound is being used.
i've run a couple setups, but currently running the Brembo 330x28 1 piece rotor. I ran 3 full track days at Laguna Seca where i was in the 120-130mph range on the front straight and never had issues with the the brakes all weekend. given, i wasn't going to 120 and slamming on the brakes to a complete stop....so again, not sure what kind of issues you were having.
before putting ducting on the car, i'd look at changing your pad compound. you might be running a compound that is too aggressive for the car. so it stops great, great initial bite, but once everything gets to temp they just overheat the disc. depending on what you do with the car, a Pagid Blue option works great on the street and track and isn't all too hard on discs either.
