Need a PM on mod dealers

I just bought a 2012 6.7 outdoorsmen. First diesel. Love it. But cannot stand the mileage im lucky to get 600km a tank in town and 400-550 towing. I bought my truck at capital. They told me they do not deal with deletes anymore due a 6.7 blowing up after they deleted it. So im just wondering if u people could help me out. I want to do 5" turbo back. S&b intake h&s mini max and thats all for now. I already have a rev tek 2" leveling kit with 35s. I am out of edmonton alberta. Also when u guys say mod friendly does that mean you did the install yourself and they accept thar or you got the work done at the dealer?

Thank you
Edmonton Diesel Fan