IMO RE headers ,rechroming vs replaceing is almost not cost effective .time you strip bead blast treat and rechrome or recoat you have some "bank" in the project. Re preserving them, mist some wd on them and wipe down after use this is about the best you can do . RE The jet out of water, "in a perfect world" the impeller shaft is suspended for and aft between rear bearing and front bushing and thus so is the impeller (has clearance between the blades and pump body), so theoretically there is no contact between impeller and "wear surface", in or out of the water. All bets are off however if bearings and/or bushings are worn. Especially on Panther the Stnls Impeller will carve into the housing like a "boring tool". Sso key here is "is your pump tight in the first place" ? Tom