PEX piping to increase appraisal. Does it matter ?

[Maugno M.]

I am currently doing a rehab on a foreclosure. 1300 sqft SFR. The plumbing on this house is all old galvanized pipes. I got two quotes from plumbers which one is to replace the whole thing with PEX and doing drainage, and the other is to replace from the risers up with PEX. Of course to redo the whole thing costs a lot more than just doing the risers up.

If i plan on doing a refinance on this home(BRRRR) which one should i do ? Could i get away with just doing from the risers up with PEX? This house is outside city limits so no permits needed.