In the quarter mile you will certainly see a gain over manifolds with any header because WOT power will be your primary gain. The difference between Pacesetters or even the TOG Extreme headers which both have 1 3/4" primarys over a 1 5/8" primary tube header will likely be very small, especially on cars that dont need them. If you had an intercooler, 2.6 pulley, maxed out heads and large cam then you will likely see a small difference. Otherwise unless someone who HAS done back to back comparison at the track with the two different headers in the exact same weather and track conditions with no other changes on the car with timeslips I really doubt you will notice the differences other than higher quality between them
