Hello mate, the only reason i used them was cos i made the manifold so i could top mount the t3 but they seem fine. i use a very high grade thread lock fluid and they seem fine. Put a steady bracket on the manifold helps but i reckon you may struggle to do this on a standard one. i have always said its as much the weight and movement on the standard manifold that causes the gaskets to blow but mike at ferridays has a good point when he says the standard gaskets just can't take the heat from pure thrashing
Like i say mate your welcome to have six.f.o.c. just let me know. i had to cut mine to length but that not a problem.Four of mine are helli-coiled.