Ok i know this has been probably ran into the ground but cant seem to find exactly the same issue. So at wot i get a choking hesitation and runs through every gear but only past 4500 rpms. It seems to get worse the harder i push the car but if it car sits a while and i get on it its not as bad. If im not in boost or light boost i have no issue all the way through the rpm range. I have done a boost test and no leaks were found. Even changing plugs has same issue. Was told my catalytic converter is clogged but unsure of that. Any help would be great. Its a 2012 X GSR

 

Had the same issue to a while back. Found out that the heat was causing the car to hesitate. It during 100 plus weather and stock intercooler. So probably heat soaked and was sucking in warm air.

 

What is your plug gap? 99% of the time it's the plugs

 

Checking the cat isn't difficult, but do you have any gauges or logging to see AFR, knock, timing, etc?