I have *not* fitted them. Tyre shop (very good one) managed to get one on a rim using over 120psi to seat it before the manager caught them using that much pressure lol.
My theory is that it is a very aggressive tyre bead shape, combined with a very aggressive rim shape. I later fitted Federal 595SS to the same rims no problem, I've fitted FZ201 to 2 other sets of rims, and obviously billions of people have fitted tyres to R34 rims. But the combination just does not happen.
BTW federal were great about the problem, sent a tech to the tyre shop to check it out, and swapped for another tyre at no cost.