there are multiple way to increase airflow without increase in noise,
if u are me, im against of mounting on the side panel, look a little bad..
currently im running my pc with only 2 120mm fan, 1 intake, 1 exhaust,
i7 4.6 ghz, a gpu, few hd, and everything is fine, its not that easy to turn things into an oven,
i dont know y so many encounter this problem..
so u want cooling with no noise?
can can mount an/few internal fan at the hdd drive cage or the 5.25 drive bay
even the no way to screw the fan, u can use cable ties to mount the fan to these drives and from the mesh at the top panel or use this
http://forum.lowyat.net/uploads/attach-91/post-17891-1322373170.jpg
http://forum.lowyat.net/uploads/attach-91/post-17891-1322373170.jpg
and use it like this
http://cache.futurelooks.com/wordpress/wp-content/uploads/2012/02/NZXT-Phantom-410-Crafted-Series-Chassis-9.jpg
u can mount the fan here on ur case
http://www.guru3d.com/miraserver/images/2012/corsair-550d/IMG_6362.jpg
the first link i shown it to make double fan mount together if u desire
u can mount the fan on the side with the foam, but u need to make hole for the fan or just use some tape,
it depend on how think the foam, if it thick then i will suffocate the fan, i have no exp with these foam