Pipers don't have SIDS but I'd doubt if a Cherokee might not be potentially as bad in corrosion terms.
Folks,
I have seen some bad corrosion on PA28, certainly the spar, including the inner spar and caps --- and where the main spar is attached to the fuselage.
Also around the tail --- all this means is that you can find corrosion where there is any aluminium or ferrous components, and that goes double for bi-metal corrosion. so corrosion is potentially going to be found anywhere ---- so look hard.
Picking up a really cheap C-172 with good engine /prop time and good avionics and rebuilding the wings could be a good deal, but personally I would prefer if somebody else took the financial risk, but you never know your luck, particularly if you have some expertise in the area.
Tootle pip!!