Ya, it came with it. I THINK I have an extra one on a shelf.
Not sure why it would cause any interference, but at the very bottom of mine there is a little bump so it can't get too close .
2012 Focus Sport, MBRP exhaust, COBB Filter/Snorkel delete, ST Wheels, Toms Tune, Shark fin antenna
SOLD2006 SAP, Draxas Header, MBRPexhaust, CAI, Tuned, FRPP lowering kit, SVT 5spoke wheels, HaloProjectorHeadlights, Mazda rearwiper, mustang antenna