Something to keep in mind as you look into "emissions on" tuning. Emissions-on tuning does not mean it'll pass a smog check in any of the 17 states that follow CARB's guidelines. Emissions-on tuning like Duramaxtuner is just that... they left the emissions equipment on the vehicle. Sure, you still have a DPF and SCR system intact... but is the truck emitting excessive NOx? Most tuners have no idea and/or don't care. As long as they make more horsepower, they're happy. DPF life shortened thanks to over-sooting? Also, not a concern.
The Banks Derringer carries a CARB E.O. That means you can drive into any smog check facility and pass the test. With the Derringer, intake, and exhaust you'll gain 98 hp. Yes, 98. This is dyno tested by more than a dozen third-party performance shops. A quick YouTube search will reveal the dyno testing.
Oh, and that dead pedal you're describing, Derringer, combined with the new PedalMonster throttle sensitivity controller will get rid of dead pedal completely.
You'll also find a Facebook group with over 3,000 Derringer owners who have millions of combined miles.