wakey is your exhaust stainless steel ?
if you rub back chrome and polish it, if you don't keep doing it regularly it will keep rusting.
if you paint it make sure you have it bead blasted or lightly sand blasted first.
otherwise the paint wont grip too well
i painted the exhaust on the Orion and it lasted well, used VHT exhaust paint.
then i wrapped it with thermotec heat wrap.
the exhaust on the PW50 has been sand blasted and painted with VHT paint too, then wrapped in heat wrap.
i sand blasted my IT200 expansion chamber a couple of years ago too and painted it, i used Duplicolor exhaust paint on it.
first time i started it after letting it dry for a week, all the paint near the head bubbled and eventually come off, the rest of the expansion chamber is still good though.
none of the high temp wrap i used is waterproof, never had it cause any problem either.