It's a change in throttle response. NOT turbo lag. Same volume of air is flowing through the turbo at the same velocity as it was before the FMIC install. The difference now, as many have stated, is that the distance between the compression point (turbo) and throttle plate has grown by eleventybillion feet. Making for less responsive throttle inputs.
A new tune will account for the change in pressure drop across the old TMIC and new FMIC, and maximize the charge cooling gain with the FMIC. But you won't see a magically noticeable increase in throttle response. Just something to get used to.
BUT, do yourself a favor, and do a leak check at all the FMIC pipe couplers. Most often you'll find a leak somewhere that is making the throttle response even worse than it should be.