I removed on my turbo due to a major oil leak and all the bolts came out without issue. Got lucky for once. I been reading everything I can on the site and read suggestions to install studs on the oil return rather then try to bolt the flange backup. I also need 3 studs for the header connection as I don't think the rebuilt turbo from Bison is going to have them installed. Where did you guys get the studs? Just any auto parts store? Once I finish replacing all the hoses and install the turbo I will go back to trying to find my mystery clapping noise.