well my three or four month journey to install a Millenia intake manifold is finally coming to close with rather unsatisfying results. After attempting the install myself and then going from shop to shop to help me with it, i finally got a mechanic to sit down with me and explain everything. The biggest difference between the two is the ports coming from the bottom of the mani. The millenia has square ones while the KLDE has oval ones. This is a problem because it the air runs into any sort of obstruction, it creates turbulance and can even hurt air flow. The way around this is to either have the heads port matched or port and polished. The first costs about $200 and still doesn't open up the flow. Port and polishing costs closer to $400-500 and really only shows a gain of 5-10 hp. However, if you run a turbo, i'm told that port and polishing is actually worth it. The other problem you run into with higher air flow is fuel management. This is another pricey part of this whole extravaganza. So are those few hp worth all this money? I say no. I don't really know about the ZE mani, but i know that this project was a waste of my time and money. well, live and learn....