Sorry, but you guy's are all wrong. The k20 head is not going to be a benefit on a k24a2 block, the head on the k24a2 is just as good if not better.
What you are thinking of and misunderstood is using a k20 type r head ore type s head on a k24a3 accord block. Those motors came with egr valves and different valve train.
Do some research, you will see what I am talking about.