I'd say it depends on the quality of the tinting. If it's been done really well, no bubbles, scratches, etc., then keep it.

@R5FORD: Only just noticed you're from Oz. Did they officially sell Sierra Cossies down under?
Why don't you drive an XR6 Turbo instead... I'd sell a kidney for one but there's no chance I can get one regularly registered over here (LHD headlights required, stupidly expensive emission tests, etc.)