The Coolmaster drivebay systems is a bit of a hassle with the T3 as it doesn't work with it. I found that you can only screw it in on one side as the holes on the other side are for the lower holes and the T3's holes are the upper ones. I found that if you bend that spring tab inwards though, it seems to hold that other side of the res fairly well.

I forgot to take photos, but if you have a coolermaster case with that latch system, you will see what I'm talking about.