Gimmick: A trick or device intended to attract attention, publicity, or business.
Not sure many of the options on the car could be "intended to attract attention" besides the paint and wheels. Although I suppose you could say they are intending to attract attention from potential buyers in the showroom... which makes virtually everything a gimmick!
I guess by gimmick people often mean "not my priority". For example Mcmaddy isn't interested in keyless, but I'm keen to have it. For me Dynaudio is not worth having yet for others they wouldn't do without it.