As far as the regulator goes, thread the fitting before attaching the regulator.
As for the DP bolts, I had similar problems, but not with Allen heads. Make sure you use a good quality tool on them. Spray them tonight with PB blaster or some other penetrating lube. Before wrenching on them tomorrow, give them a good sharp whack with a ball peen hammer. If that doesn't work, you can always heat them with a torch, but that didn't work for me.
When installing your NEW turbo, put some anti-seize on those DP bolts!!!
As for the DP bolts, I had similar problems, but not with Allen heads. Make sure you use a good quality tool on them. Spray them tonight with PB blaster or some other penetrating lube. Before wrenching on them tomorrow, give them a good sharp whack with a ball peen hammer. If that doesn't work, you can always heat them with a torch, but that didn't work for me.
When installing your NEW turbo, put some anti-seize on those DP bolts!!!