Maybe just MAYBE there might be a dedicated M4 Track Car. Autoevolution is saying just such a thing is in the works...
http://www.autoevolution.com/news/exclusive-bmw-working-on-m4-gts-84690.htmlWhen the new BMW M4 was launched there was some talk going around on the internet about an upgraded model, similar to the GTS alternative to the normal M3 before it. Well, our kind, reliable inside source with the Germans just confirmed to us that such a model is now in the works.