I'd try something that semi-works first to see if the engine can even handle the extra heat. If it works, then you can make it a better system. The 1ZZ-FE isn't a low compression engine and hot air may cause it to retard ignition timing. Start by pulling air from around the exhaust manifold and see how warm that gets you. If you see your ignition timing being pulled on the highway then you probably won't see much in the way of mileage gains. I don't know anyone else who has played with the 1ZZ, so I can't say how it'll react. Of course I'm interested as my Matrix has the same engine.
