I have the same spring setup, and I used to have 17x7" rims...I ran a 205/40/17, which is closer to the stock overall tire diameter. I think 45's will be too big. I had the old school paradas on them, and on my 16's I now have the AVS ES100s. Both are good tires, the AVS will perform better in wet weather.
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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