My stock pump with stock sticks could maintained 2800 psi on a PHP 140 tune, it could not maintain over 2200 psi with my 175/80's, PHP tuning, 2.7 ms PW.
Put a new pump in, MB stage 1. same issue but was maintaining about 2500 psi. still 2.7 ms.
Put a MB stage 2 in, maintains 3200 psi all day now.
Im not the only person that has had issues holding PSI with the 175/80's.
I may have some other issue going on that I could not track down that was causing my low PSI? But in my experience a stock HPOP will not support 175/80's.
In the end, my truck runs real strong. Very efficient, not much smoke unless i really lug it, lights the turbo at about 1200 rpm and it tows very well, better than my fathers tuned and ******d 6.7, this may be due to the auto though.
I dont have experience with other injectors other than stock. I would really like to try some hybrids and see how they perform.