IMHO the dyno is an expensive tuning tool and your dyno results are something you can brag about/or not. Once you establish a baseline, your time slips can be used to determine if a bolt on, or bolt on's, have changed the performance of your truck. This includes any mod or combination of mods. The Vararam is more effective on the highway and/or at WOT. I agree that there are many variables when racing ie; traction, weather, and most importantly the driver. Considering the experience and the results that Matt has over the years, I think that the information he gives is accurate and most importantly, track proven.
Jay