Scott
Most definitely go to walmart or any automotive shop. As for Hightemp engine, muffler paint in a rattle can. Wire brush the bypass, clean it up with acetone etc, and spray the pipe applying a couple light coats over 25-30 minutes.
While your doing it, make sure the wife isn't home and pre-heat the oven to 400!
let the pipe dry for an hour or 2 then place he pipe on like a pizza tray or somthing and keep it in the oven for a half an hour or so. Open a window!
Every-time I do this I usually get yelled at a bit, but the finish lasts a hell of alot longer than it does when I just spray it and put em on. It will look good for quite some time.
JW