for reals people are all for aftermarket intake manifolds, but i would say get the d16y8 intake manifold. When you see it you would know why that manifold is so different from others. I've seen the intake myself and its the one i plan on using for my next engine. I dont know how much you can port the manifold if any , but thats something I'll be looking in to. If you do some good shopping you shouldn't have trouble finding one for under 100$. Why pay way more money for an aftermaket intake manifold when really you wont but able to tell the difference. The dyno might tell you different, but i doutb you or I would. ie. $200 for 5-10hp if any. dont get me wrong 10hp is a lot , but i can tell you 10hp wont win the race for you. just my two cents.