First I would check to see what OTHER parts need to be changed.
In SOME cases, turbo (or supercharged) engines require different heads as well as different exhaust and intake manifolds; also different timing which can be expensive if you need more than a "chip" upgrade or change.on the newer computer controlled systems; also possible fuel system changes, etc.
THEN you can figure on about $1000 MINIMUM for the complete turbocharger unit.