this is my friends profile but i was running the fujita stage 2 w launch control no ac or data logged. i have a fujita sri strup header and skunk 2 70 mm with the resonater cut off cuz i broke it. idk what cels are?
When you say it is coughing and sputtering, did this start to happen AFTER you installed your catless, non-resonated exhaust? It sounds like you have what amounts to a straight pipe which is going to make a fair amount of noise. Did you make any changes before you started noticing this "cough"?