Only way to know for sure is to log it. Also, it's not just the heat soak but the amount of boost it pushes. I believe Stage2+FMIC peaked around 18lbs for me at one point - not sure how well the stock hardware will hold up to that.
In all honesty, if the manufacturer says FMIC is required, they say that for a reason. Just get yourself an ETS 5", it's $770 and requires no cutting