nope, never on a car unless its got a stainless steel manifold.

had too many blow, on countless different cars, and theyve never blown again once ive removed them.

Cossies, R5GTTs, RSTs, S12s, S13s, S14s, etc etc, ive either owned or mates owned, and removed them and been fine since.

Dont really get why they there considering the amount of ones over time ive blown.