I seemed to have posted this in the wrong thread. Anyways heres my newegg review that inlcudes the measurements for the hardware you need for a 2nd fan:
Pros: My Idle temps dropped 10C and my Max temps dropped 20C.
Im not going to give specific numbers because those change based on your ambient temps.
All I can say is, when I installed the H50 it dropped my MAX TEMP to that of my old IDLE TEMP
Other Thoughts: Install on an Antec1200 Case requires you to install it in the lower 120mm fan slot. If you try to install it in the upper 120mm fan slot it contacts the 200mm topfan.
Also it doesnt come with screws to install the 2nd fan, and in my case the case screws that the fan usually installs with were all wrong. So for a 1" thick Fan you will need 6/32 diameter metal screws with a 1 1/4" length. Lowes $1.18