The only reason to turbo charge a NA car would be so you could insure it as a standard 2.0 GL although in doing so you would immediately invalidate any insurance you had as you would be declaring it as something it wasn't. In fact if you did insure it as a turbo charged GL your premium would probably be more than it would for a genuine UK turbo as you would have to have a modified car policy.
Much easier and cheaper to just buy mine off me
