no one in here actually know how the SOHC is choosen for whatover .
but as far as i concern , those engineers are not nut . they know the advantages of DOHC and SOHC , they chose SOHC for reasons . yes , the DOHC is better in terms of technology ... bla bla bla ... but the SOHC too have somethign that DOHC can't archive . and it all depends on what u want , how u refine it , how u engineered it .
not becasue of tech , is becasue of they are choosing what they wanted .
cost cuttng , nah ... who the heck want to cut cost for such big and pricy car . don't tell me rolls royce is cost cutting too ... ferrari cost cutting , those manufactures doesn't need to cut cost on such thing .
investment is very important .
bmw engine more refined than merc . should be conclude that beacsue merc is SOHC so that it cant archive refinement . merc invested more on the car itself while bmw invested more on power , engine , drivability .