I have no way of measuring the intake air temp. The best I can do is pull the door off the case for a while and see if the discharge air seems cooler.
I just got a response from Antec, and they are going to send me a couple sets of case feet to elevate the bottom of the case. I will make a decision when they get here. This way I can still have the "stock" look.
The only reason I question the need, is that I have been swapping my video cards around, and the temps for the bottom card is always about 6c warmer no matter which card I have in the PCIe 2 slot. I have three total between two systems.
I'll do some more fussin' to try determine if there is any real benefit. I have a CM Storm that uses the bottom intake, and it seems to discharge cooler air.
I don't want to hack up a case unless there is a benefit besides appearance.