i have had my exhaust system for over a year now prob the same time with the flamer kit and it's still in good working order.
the flames come out the tip of the back box where the spark plug is so i cant see it doing any damage to the exhaust.
for the bumper had no probs with it it's still there lol.
for pc plod? i have no probs with them but had some realy close calls. ie 1 car behind a traffic car on the m way i did not see them but thats life.
if i ever got pulled by the pc plod i have a excuse for it lol. need to try it out to see if it would work lol.
wullie