Many of you that have removed the headers, will recognise the problem. When you unscrew the 6mm nuts, there's the risk the dito studs will turn too and on fastening there's always a chance the thread in the head turns out to be damaged. The last time I had to removed my exhausts, it was my turn. Three of the eight studs gave problems. A friend, who had every reason to be grateful btw, helped me solve it. He, a yacht mechanic, preferred to use Timesert, which is indeed a great invention. The question remains: is there a way to avoid as much as possible such a repair, in other words is there a trick on loosening/fastening these 6mm nuts? Is it better to do on a cold engine, or do you have a better chance when the engine is hot? What can one do to prevent future problems? Has any of you tried a slit in those studs, so in future you could use a screwdriver to keep it in position whilst undoing the nut ?