My brothers bone stock '17 3500 needs injector(s) according to the dealership, 5k out of warranty of course. They want stupid money to put remans in and I'm not comfortable with local shops so I told him to buy new and I'd help him do it. I've done CR 5.9s but never touched or even driven a 6.7. Any tips or tricks, parts to replace while I'm in there, etc?