[strictlypersonl]

If applied correctly, VHT-type paints won't bubble, but they do chalk and wear off in time. We recommend re-coating about every year. They have the same loss of effectiveness problem as the ceramics below.

Ceramic coating is permanent but can stain from external contamination. If the ceramic coating is on a "housing" that encases a standard bullet muffler, they tend to get louder over time because the packing loses its effectiveness.

Stainless exhausts tend to have baffles, and should last forever, but typically will yellow or blue in the hottest areas. Most of the time, you can polish that out, but the discoloration will return eventually.