Looking at the fastest truck list I see a 5.3 4wd with only a Nelson tune and intake at 15.4. My truck, 4wd, 5.3 Intake, Exhaust, Headers, Efans, Nelson tune recently ran 15.8. I really don't see much room for improvement in the launch. Launched 2wd and 4wd and went from 15.885 to 15.865. What gives? My truck just slow?