Black smoke = rich
Burning oil = bluish/white smoke
From your previous problem of bogging under boost, I think you're running rich once you step into the throttle a lot.
If you want to test valve stem seals, get a leakdown test done. As for the dipstick, I believe STR makes a billet one.
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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
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