I've had good luck with my ISSPRO'S..white face blue dials, though they do make other colors. Check with Dieselmanor..hope I'm allowed to say that..:biggrin5: Their gauges come with great instruction (pic's) and more stuff to hook them up than you will ever use.
Not unless your in a real dusty area..but it would still be a wait and see type of deal...I've had mine done for a year...and I don't go through filters any sooner than before I did the mod..Although, I change mine out sooner than most.:sifone:
I have the PPE valve..some guys have said that they don't "feel" an increase in a totally stock dmax, most see a increase with some type of tuner, and possibly other mods, i.e. exhaust, cai ect..You should see a bump in boost, i.e from about 22-24 psi to 26-28 psi, having a boost gauge will...