I have the aFe and I am currently awaiting arrival of my TRD. They are exactly the same but the aFe has an inlet hole as mentioned above. aFe has a plug for it now.
If horsepower is such a big deal, I think you should save up for a supercharger. I think the stock intake is well made out of the box. However, I purchased my aFe for the look and the sound.
Does 10hp, 15hp, or 18hp really matter to you? Are you racing it? Does every single penny count when it comes to MPG? It's going to take a while for any intake to pay for itself in gas savings.
I went with the TRD to stay with the TRD edition theme. Is it all vanity when compared to the aFe? Yes, and I don't care because I spent my money on it.
I'm sure you just want to maximize what you get for the price you pay, but I don't think there is enough solid evidence that one is "better" than the other. Go with something you like and can afford.
