I installed all of my fans at one time so I can't give specifics on which made the most improvement. Here is what I did to my Enlight 7237, I put two Sunon High Output 80mm fans in the front drawing air in. Each fan draws 42.5 cfm (85 cfm total in). I put a 92mm under the power supply and another in the top (blow hole). The 92mm fans exhaust 44 cfm each (88 cfm total). The theory behind this set up is the 80mm's suck the air in to mix with the hot air in the case which is forced out by the 92mms. The intake and exhaust are fairly "balanced". My CPU was running at 48C under load (measured with ASUS Utility, not super accurate). Load was playing Quake 3 Arena for about 90 minutes. Now after adding the fans my CPU is about 39-40 C. I am running the ALPHA PAL6035 with the black label Delta fan. The ALPHA HSF was installed prior to the fans.
Does this help at all?