I had Dynotronics flash my Gen4 with Yosh 3/4 exhaust. Result - perfect fueling, better bottom, much better mid range and crazy top end. All restrictions removed - no PC needed nor recommended - runs smoother than my 14. Fuel mileage is even better if you can control your wrist. Why do you guys insist on going with the PC when it adds cost and unneeded complexity and the maps for the most part are junk. With 180+ hp whp from the re-flash the possible nominal gain from the PC and a custom tune is not worth it to me. There are zero drive-ability issues with the re-flash. The Dynotronics re-flash is very good.