People can add duel exhaust or put 5.0 symbols on their cars...(posers)
BUT the #1 way to tell the 10' from 11'??
The 2011 mustang has sidemirrors with a convex mirror built into the far upper corners on both sides. Dead giveaway.
If people can add a dual exhaust, they can add the mirrors too then. I've added Euro-spec split mirrors to other cars before to eliminate blind spots.