I don't see carbon as a problem in a 2.4 as the only source of contaminant is the PCV and the air cleaner, so I have used Seafoam in both the gasoline and the oil on ALL my engines. on a 2.0 the ready source is from turbo lubricating oil.
Every direct injection engine will eventually experience carbon deposits on the intake valves.
Without fuel spraying onto the valves to keep them clean, they will foul. How soon or how bad depends on the engine and driving habits.
Every manufacturer is experiencing intake carbon deposits since introducing DI engines. Some are fitting an injector in the intake port, in addition to the one in the cylinder, just to clean the valve with a spray of fuel.
The type or quality of the fuel, and adding fuel additives does not reduce the buildup since no fuel travels through the intake passage.
An oil catch can will reduce carbon deposits but finding one that actually removes oil vapor effectively is a challenge. Google oil catch can or DI engine carbon fouling. There are hundreds of posts, blogs and forum discussions about their effectiveness. And some pretty good arguments.
The problem adding an oil catch can to the 2.0 GXP engine is the inability to connect to the PCV system. The PCV valve is buried in the intake manifold and dumps crankcase gas directly into the manifold. Wife GXP or somebody else has modified the intake manifold to inable an external PCV valve and a catch can. There are pictures and a description on the forum. That modification is the best way to remove oil out of the crankcase vapor. I bought a spare intake manifold to be modified for the PVC relocation. Project # 798 out of 9,999 awaiting projects.
I have a catch can on the turbo side valve cover to the charge pipe that hardly catches anything. It's not the ideal location since it only has vacuum during turbo boost. The PVC in the manifold has vacuum all the time except under turbo boost. That is the best location to add a catch can.