Rcurley55 is on the right track i also use 2 fans in my power mouse boxes. but i blow air into the rack. the hot air rises so it is better to aid the air moving up and out of the rack rather than try to pull it down and the opposite way the air wants to naturally flow. i also use 2 fans. they are only 2 3/8" fans but i did a lot of searching and found them to be rated at 18cfm each. for a small fan that is really good. they also have 100% ball bearing and brushless motors so they last forever.
i use mostly class d amps for the subs so they dont get that hot. all you need is a slight breeze to keep them cool.