2 years ago I put on Pacesetter Headers and used silicone on both sides of the gaskets as recommended. I only got 2000 kms of use before one blew and they were re-tightened as required from the beginning.
I then ordered the cardboard type gasket that Pacesetter sells, soaked them in warm water for 30 minutes, then installed them on bare surfaces without silicone. I have since gotten over 20,000 kms and no problems since. Best job I`ve done yet, if this helps.