well not necessarily... according to this quote from engine mods#2...
"The F2 intakes use a removable urethane insert (reducer) inside the tubing, while the Fujita’s reduction is part of the tubing itself. A good thing about the F2’s removable reducer is that once there’s an available MAFS to take advantage of the 3” tubing, all you have to do is remove the reducer to make even more power. Power will be further augmented by the ECU/fuel tuning once it’s available as well."
dont know what a MAFS is, but it sounds like pipe diameter matters...