Agrees with lolwenli, i will opt for more exhaust anytime over more intake. You can only cram so much air into a case but its useless if you cant purge the hot air out ASAP.
Please also bear in mind NON of the cases in the market is airtight, not even close rofl.

Initially i was thinkin of gettin a cm690 to mod but after countless night of consideration i went for an open workbench concept, granted this will NOT work with most ppl due to many factors - insects/kids/space constraint/dust/maintenance but so far i've had a comfy 2 weeks with the setup and temp issues are now a thing of the past.