How to replace the exhaust manifold on Gen2 prius?

Took my prius to replace the oxygen sensor for a P0031 code that I had and the dealer's guy said I need to replace the exhaust manifold as well. I'd rather use an independent guy that I use since the dealer quoted me $900 just to replace the exhaust manifold. Does anyone have the manual to replace the exhaust manifold? Can a "regular" car mechanic without any hybrid experience replace the manifold or do I really need to have the dealer do the work?

 

But it can be done by a "regular" mechanic? I don't need to take it to a Toyota Dealer or a shop that specializes in Hybrid? Where can I find the manual so I can give it to my mechanic?