If you have the room in your case a push/pull configuration is the best, it's a bit louder but the efficient flow allows you to slow them down a bit also.
Liquid Labs did a nice study on the effects of all the different set ups and is a great read, perhaps take a look at it, Martin is the best water guy I have ever found on the net for rock solid info, enjoy..
http://martinsliquidlab.org/2012/06/08/hesmelaughs-radiator-sandwich-testing/