It's very hard to judge impact of a show on any sale of a particular motorcycle. Impossible to prove, it's all just speculation when someone contributes sales to a TV show. The GS has been, is and will be the best selling large cc adventure bike world wide (mainly in US I believe). Advertising wise surely, it was a win for BMW, but did it help significantly increase the sales, I seriously doubt it. Was it an advertizing flop for KTM, undoubtedly? Did it cost them significant sales? I doubt it, because any sensible person who does real and long adventure trips, with a lot of muddy off-roading and unpaved roads would pick the KTM anyways, regardless what Charlie and Ewan chose to suffer (and you have to admit some of the episodes were hilarious, I felt for them ....) through in the movie ....