all engines turbo or N/A suffer from some heatsoak after shutdown, some manufacturers hook up their thermos to run after the engine has shut off (honda for one), but the effectiveness of this is another story all together (seeing as tho the water isnt moving, it may just be to keep new air moving into the bay.
my 1G only rises a few degrees after shutdown (id say 5 at most) so i am not bothered with it.
if your really worried about it do experiments with a temp probe or your temp guage after shutdown with and without the fans
an ideal situation would be to have the fan AND the water pump running for a while after shutdown, which could be done if you had an electric water pump.