I took someone else's advise from on here and started soaking the exhaust studs with wd40 for a few day in advance. It's a known fact that the tighter the nut the more wd40, ha ha, I can't remember how many hours mine took, but it was all in one day. I know I paused for a coffee a couple of times, every time I came upon a stuck nut I sprayed more wd40 and let it soak in,