It's the option of not having that Mustang stripe that is normally installed on the bottom part of the door on both sides of the car.
Is this applicable to the GT? I looked at the order guide and it only shows up as a V6 option. Don't know why the salesman would put it on there.
DELIVERED: 2011 Mustang GT 5.0 Premium, Kona Blue, Black Leather Interior, HIDs, 3.73, Security, 19 inch Painted Aluminum Rims - Roush: Front Valance, Front/Side Splitters
Washington State 5.0 Owner's Thread: