stgIIs4

This is my first summer with my s4 and it runs hard as hell, but when it is humid it seams to have no where near the power it usualy does. Tonight after she warmed up i was on the highway and it felt very fast but after about 10 minutes it seamed like it lost a significant amound of power. Is this just heat soaking bc of the weather? Im assuming so but any opinions would be appriciated. Thank you.
btw it was 97% humidity, car has GIAC 93 tune and borla cat back.

quickaudi:STFA

stock intercoolers will do that to you.
try upgraded ICs and some water/meth injection and a retune - couldn't hurt