Go with 1 thru 5 of what Dan said. Put the strongest fan in the back blowing out, to take advantage of the cooling slots in the side of the case. When drilling the bezel, hold it down tightly or it will want to climb up a spiral bit as the bit breaks thru the far side.
Before you go for the blowholes, snip away the stock stamped fan grilles, remove any airflow impeding plastic from the front fanholder, and install a wire grille on the rear fan. Put one on the front fan if you think it's a good idea, but it's not really necessary. Remove everything from the case before you cut it, get all the metal shavings out, for obvious reasons.
A 7237 begs for mods, particularly the front bezel. A great deal of the apparent airflow from the front fan is actually air being recirculated from inside the case, behind the bezel, back into the case. Just blowing warm air around in a circle.