OK you're wrong and I'll correct you. OEM's typically go for best filtration on intakes, not best flow. It's a balance. Aftermarket is the opposite, max flow at the cost of less filtration.
A good aftermarket intercooler will absolutely allow the motor to make more power, thinking otherwise is wrong. IAT's are very important to keep low - the stock IC sucks big time, it will get overwhelmed during ONE dyno run. Ford even says to not mount the license plate over the IC grill if desert running. There are 2 benefits to a good IC vs OEM. Lower IAT's (and more consistent) and lower pressure drop, meaning it is more free flowing. The higher ambient and the more heat you are pushing through the system, the more beneficial an IC will be. With winter temps, a better IC will be less effective than in summer temps but it will always be better.
Free flowing exhaust is super important to turbo vehicles, any back pressure is a detriment. I have no idea how restrictive the stock CATs are or the stock exhaust is but I would bet anything there is ~20HP easy from a freer flowing turbo back system.
Many years ago I had a Volvo S60R - 5 cyl turbo 300HP motor. Some avid enthusiasts did some testing and found that the STOCK airbox would go into vacuum at full boost, meaning the motor was requesting more air than the stock intake could provide. This was proven with a manometer. IIRC the airbox would achieve -3 psi in vacuum. Point is, not all OEM boxes are created equally. There are companies out there that have dynos proving HP gains with intakes - just remember it's at the expense of filtration. Not saying this is happening with the Raptor as I've never seen anyone test it.