1st I would double tape and use a cut up plastic trash bag on the bumper and surrounding bumper areas. Any automotive store should sell a decal/paint remover product. Brush or spray. The spray will work just fine because it comes out in a small pattern. You may want to tape off the chrome on the pipes, but if you wipe it off immediately, it shouldn't be a problem.

After about 10 minutes wait, a good product will have the paint wrinkled up and falling off. With latex rubber gloves, wipe out the pipes, even use steel wool at the same time if it is tough. You may even have to apply a second coat to get it all.

I have not stripped my pipes, but plenty other items on other cars.

Good Luck, James