Not worth buying a skunk2 intake manifold, if he already has a type R. That would prove to be a waste of money, that could be more beneficial if that money were spent elsewhere. 5-8whp is absurd, there is no way. I have not seen any specific results first hand with the AEBS, so I am not personally sure about that manifold. The fact of the matter is, the intake manifold is not the limiting factor here, let's all move on. If you are looking for further gains, a different header or even different cams, would be the next logical step. Otherwise you are good for 13's as it sits, tuned properly.