The BMW M4 is a sublime sports car that combines sizzling performance with luxury and everyday usability with aplomb, but, in the hearts and minds of some purists, perhaps a tad too well. Whether the M4 ultimately lacks the sound and fury demanded by the most ardent M car aficionados may be debatable, but BMW has moved to silence the M4’s critics by offering a catalogue of OEM-approved aftermarket parts to give the Bimmer a more hardcore edge.