Is it sacrilege to put a turbo in an M-class car? What about twin-turbos? No matter, sins aside, the new twin-turbo inline six (replacing the naturally-aspirated V8 of last year’s M3) is a spectacular performer. Power delivery comes on strong and early and encourages short shifting, versus the tradition of wringing power out of the top end of M-model cars. That doesn’t mean you can’t rev the bejeezus out of the M4; it just means you don’t have to. BMW says the smaller motor means less weight and enhanced handling, and this would be hard to argue with since the new M4 is grippy, transitions like a trooper and can still wag its tail if encouraged to do so. Natural selection is a fact of life and, thankfully in the case of the M4, the strong has survived.