14L Detroit turbo upgrade

The truck is a 2007 western star 4900 14L detroit 515hp &18 speed. I'm looking to get rid of some problematic parts and need help with part #'s to make this happen. I'm just looking to gain reliably, mpg and a little hp, maybe 600. 171702 turbo seems to be the go too unless you all have differing opinion. What I'm looking for is part #'s or a parts list for everything else needed to make this happen. Oil supply and drain, turbo elbows and boots, the coolant tube that runs to the water pump, will I need a new down pipe? Also who do you all recommend for tuning?

 

10-4
I've seen a lot of mention of leon in my research I've done on the detroit stuff, how do I get ahold of him, any contact info? Also can I use the factory exhaust manifold with a block off plate?