"Keen "to replace V6 with inline Gas engines

Those old long stroke I-6 engines were great for torque, easy to service without all the pollution control gadgetry but horribly inefficient and 'dirty' by emission standards. The V-6 allowed a shorter more aerodynamic vehicle but are difficult to balance,anyone remember the funky odd spaced distributor cap terminals on some? The even fire engines required a very expensive crankshaft with offset journals.
Mercedes and other high end manufacturers of rwd cars likely want to return to the smooth quiet of the I-6 and have found ways of meeting emission targets.