Bit late but hope you sorted it. It is very common but is not a characteristic of the car, as bloke has said a few times they should have a nice smooth idle, I recently purchased one with the "lumpy idle from factory mate" people say this a lot even the seller was told this and passed the info on to me.
Inlet Cam timing was out, it's about half hour to check but tools are recommended for accuracy but is possible without if you know your f4r's. For peace of mind I've always changed my cambelt as soon as I have purchased a car so if you plan to do this it may sort it, if not check parameters and start looking for sensors like map air leaks and don't rule out the pas sensor which can cause low revs and intermittent stalling when parking etc (can weep PSF get dirty and cause connection problems).
Going ocd on it and cleaning abloute everything unplug electrical connectors spray contact cleaner, get the gunge off the throttle body etc don't be put off. they are going up in value so you wouldn't loose much on it if you should it on.
To contradict they do run a bit lumpy when cold but does clear after 20 seconds, due to the nature of a direct injection engine, injectors have to put up with extreme conditions have can start to wear and slight dripping of fuel into the cylinders can occur, once this clears it's pretty smooth.
