it won't affect it much. Air inside the computer case is usually 3-5 degrees higher with good air flow, so thats how much higher the temp will be by putting it on the exhaust side.
With bad air flow however, it could be as much as 10 degrees or more. Looks like from the ammount of fans you have, the air flow should be pretty good.
One thing to keep in mind, you can't reverse the air flow from your ps or the graphics card. trying to reverse the flow through only half of the case may end up worse.