I have a Hayden mounted onto the grille support. I plumbed it after the radiator, not sure if people usually eliminate the radiator or not when they add these. It lowered my temps *significantly*.
For the gauge I went with a glowshift because it was pretty cheap and I like to gamble. I’m about 18 months in, zero issues. One thing I’ll say is that if you don’t install the gauge before you install the cooler, you won’t really have any idea how much it helped. Mine lowered temps by ~60 degrees.