I will assume youre going to remove turbo from engine then.
You can see the butterfly housing (upside down in this pic) unbolted from the turbo here. Unhook the actuator arm, take a die grinder and grind off the two rivets that hold the butterfly to the shaft. Drive the shaft out of the housing and get two 3/4 inch freeze plugs to drive in the holes where the shaft was. Just that simple, valve is no longer a restriction.
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In this picture you can see the pedestal unbolted off the bottom of the turbo, on the back side of the actuator there will be a snap ring, remove it and pull the back cap off of the actuator and pull the valve out of the barrel. Flip the pedestal over, drill and tap the arm exit hole for a 1/4 inch pipe plug. Insert pipe plug and reassemble everything. Enjoy your new found unrestricted exhaust.
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Here is a link to an article on turbo removal.
Turbo Removal WIKI