no matter how good the flow rates are...infact i would have thought that those SMIC which are like cubes would create more lag due to being deep. think of it like running a hose. That's why the TT twin side mounts with a cross pipe work well as standard and efficient for the levels as they gradually cool the air from to the other not all in one go in a deep cube shaped intercooler.
anyway FMIC has a long contact area against cold wind, a SMIC has a very small contact area... Therefore what Nick's found on the thousands of cars hes tuned seems right.