I'm feeling peachy so I'll answer your question, but you can do the extended research.
If you go with a bolt-on turbo (Non-CT upgrade), you'll at least have to get new oil lines as a new bolt-on likely won't work with your stockers.
If you go with some cheap eGay turbo, Holset, or anything else you can get your hands on with External wastegate...
You'll need awastegate, some custom piping, new downpipe/elbow, likely new accordian pipe (if larger than 3"), new exhaust manifold, probably new air filter (if you're using a turbo with a larger inlet)
And additionally, it's not recommended to upgrade a higher flowing turbo without upgrading your fueling system, and if you want to do it right...
550cc Injectors, Lexus AFM (good match with 550's), AFPR, Wideband, Something to tune with and most importantly.........
I'll make the assumption based off of all your previous threads you made...
You'll need to find a reputable machine shop to take your motor to.
Have your head and block resurfaced reliably enough to put on a good headgasket and buy some ARP hardware......Because bigger turbo = bigger power = blows up if you have stock headgasket.
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/thread.
-Jeff