Anyone can buy the S badges, mud flaps, rear boxes, suspension parts, even the leather dashes were being fitted as options to the standard car by dealers such as Mangoletsi. The official "S" suspension parts are very expensive to buy (for no particularly good reason other than they have pro drive branding).
HOWEVER, I'm not sure if you can get the "S" headrest plaques aftermarket. They could be the giveaway.
To be honest though, I don't know what the fuss is about, there's very little difference between the 2 cars, the engines and performance are exactly the same, so other than some limited edition trim, the only real change is the suspension, which has good handling, but some regard as too harsh for any distance driving. Of course, like any car, the standard model can be given various recipes of suspension to suit individual taste.
Brat Pack no.8