Well now you'll have to give it a chance to learn the engine again. I had to do this for my GTST when I put the intercooler on and also when I put the pod on. There's actually a procedure to *helping* the eccs learn...like, a set way that you should drive it so that the computer can fine tune all it's tables (seeing that all engines are different but the computers all have the same maps etc etc) But yes, if it's chuggy/surgy I'd go over all your vacuum lines, pressurised pipework and all your sensors. Give it all a tighten-up and clean with contact/carb cleaner - your engine will love it (even if it doesn't fix that particular problem)