Yeah, it's very rare to get the crossover bolts, or the rear manifold to downpipe bolts out, without breaking them. They get rusty, and get heat cycled until they are literally bonded to the exhaust.

Make sure to coat the bolts so they dont rust again, and rotate tightening the bolts (dont tighten 1 all the way, then the other, and so on) That way the crossover seats correctly.