Did you not install it or have it on and take it off for a particular reason?
If temps are accurate that people have posted here some of the aftermarket coolers are making 20 degree improvements over stock. If that is in deed accurate I'd think that's enough to make a difference.
I haven't installed it. It's sitting on the shelf in my garage. I posted a photo earlier, but here it is again. It's the one on the right, the left one is for my FocusRS, but it is waiting for the big turbo (seen in photo on shelf under the Raptor FMIC) install. It isn't needed until big turbo...
As for the temps posted, I won't deny that they are seen by those posters because I've seen similar temps as well, depending on the current conditions. That's why I still say an intercooler upgrade isn't needed to maintain performance if you have stock turbos. If you're wanting to go bigger turbo or run the stock turbos above their efficiency range so that you get much higher than oem intake temps, then an upgraded intercooler is definitely recommended.
If the question is can the stock intercooler become heat soaked, the answer is yes, BUT so can an aftermarket FMIC. Will the aftermarket FMIC take longer to reach that max temp? I say yes it will, but if you're asking for max performance from the engine when the conditions have already heat soaked the FMIC, then you're not driving on the street, or you're just street-racing (drags or other slow-speed airflow limited events).
One of my previous ecoboost cars had the 1.6 and I had it cranked to 44 psi MAP, so the little turbo was puking it's guts out (I didn't care, I had a bigger turbo waiting for install), but the car pulled like a freight train. I definitely had an aftermarket FMIC in that car.
All said, I think that the stock intercooler is fine for anything less than 35 psi on absolute manifold pressure (MAP) which is roughly 20 psi boost. If I think something is necessary, I do it regardless. If not, I don't do it until needed.
