You could always put the stock tune back in and hollow out your dpf and slide it over your front pipe and take it in...
couple things....Putting the stock tune back in does nothing, they will still see it was tuned. I also have a 5" exhaust. Also no DPF to put on and no way to hollow one out really. Ill do the WP myself before I try any of that stuff lol.
Also If a dealer says they cant do it because I tuned my truck, so be it, I have no issue with that, I knew that before I modded my truck 2 years ago. If there is a dealer that will, then Im happy, Im not going to lie to them and develop some bad relationship with a dealer here over a water pump.