I am having a meth kit installed soon,but in general there are so many variables at play in order to achieve great ET'S,proper AFR(air fuel ratio)knock readings,compression,detonation,also depending on mileage to check for carbon buildup,elevation,tires,boost pressure,the items mentioned alone will give you poor et's,always recommended new plugs gapped at 0.30 with a 160stat and if your running meth,a few runs on the dyno to monitor your cars output,in order to achieve the most from your car,so basically there are so many factors to take into consideration,one importanly is to have your car checked out,looked at.