2015 Bmw M4 Coupe HD Wallpapers Free Download. The all-new BMW M4 Convertible arrives in US showrooms late this summer to join the M4 Coupe and M3 Sedan. The 2015 BMW M4 Convertible is powered by the same BMW M TwinPower Turbo.That engine produces 425 horsepower and 406 lb-ft of torque and can be mated to either a 6-speed manual or 7-speed M-DCT transmission. The new BMW M4 Convertible makes its world debut at the 2014 New York International Auto Show. great shine look wallpapers free download for desktop, laptop, pc, ipaid.