If you are looking strictly for reliability, do a CCV mod (which doesn't require removing anything). You could do an Air Dog, but I have read they don't perform well in extreme cold so if you are still in Alaska, that probably wouldn't get a good option. With that kind of mileage, your HPFP may be getting weak so you could replace it with a new one (although that seems like a pretty big expense to me unless it is known to be failing). Hopefully someone can chime in about the HPFP. I know when aftermarket ones have failed, they can take out the injectors, but I am not sure if the same would happen with a factory pump failing. I assume your DPF is already deleted and I know you deleted your EGR already. You should be good to go for reliability unless you have a broken rocker (which you can check while you are in there).