The exhaust for an ITR would fit the 00-01 GSR, but it would be the same...it's not better or anything because it's made for a type r. Now, the OEM type r exhaust is better than the OEM gsr exhaust, but not as good as aftermarket.
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
Team B.O.B.® - Ballaz on a Budget