When disassembled, you can see the direct flow path for the best flow of the intake runner and how they were staggered inside the plenum so one runner won’t steal the flow from another. Since the top of the plenum can be removed, if desired, the runners can now easily be ported.
Here is a look at the stock intake manifold, like the previous view from the bottom of the manifold, you can see how the OEM intake has less plenum volume than stock.
To start the installation, the intake manifold cover is removed as well as the coil covers for the valve covers. After that the intake manifold bolts can be removed which allows the OEM intake manifold to be lifted off.
All the direct injection stuff stays in the plenum valley which actually makes the installation easier.
