I've heard of people dropping 2 tenth's or so with a dutt neck, I would think that .2 would be very feesable if you are pushing the boost hard...The Dutt neck made 30 HP on a pump gas tune in my car (I changed it on the dyno so the straps, air temp, ect. were all the same)...Also I couldn't run as much boost with the stock neck as I can run with the dutt neck (pump gas)...All in all I thought it was a very good investment.