Headers vs. manifolds

My uncoated TTIs are still on the car, since 1999.How many years is that now? Cheapest headers I ever bought. They are at over 125,000 miles now...
But the merges are leaking.
Again.
Not so the flange gaskets. I replaced them once in the interim, not because they needed it, but because they had been reused about 10 times already.