saloon to be powered by a high-revving engine, and as the recent top-performing versions (usually the BMW 760Li) have V12 engines which while powerful are considered too heavy for a sporty offshoot. So far the unofficial "BMW M7" is the Alpina B7, which is produced on BMW's assembly line though its engine and finishing touches are done by auto tuner Alpina. However, as BMW M shifted to turbocharged engines, there are rumors that there is an in-house BMW M7 in the works, and it is speculated that its performance may exceed that of the BMW 760Li and Alpina B7. The BMW X5 and X6 sport activity vehicles received M derivatives for the 2010 model year onwards. These are the first M vehicles with xDrive four-wheel drive and automatic transmissions, and also the first M-badged SUV models. However, the E70 and E71 X5 and X6 M were actually developed by BMW Group rather than by BMW M. Although these are considered the most well known in-house tuning divisions, BMW M has a considerably different philosophy than Mercedes-AMG. BMW M has emphasized tuning only vehicles with "Lateral agility" (which has long been the 3 Series, 5 Series, and roadsters), while AMG has created high-performance versions of many of its nameplates, including flagship sedans and SUVs. Accordingly, "an M car has to be responsive and fundamentally keen on turning as well as accelerating. The M5's technical spec is all about connecting the driver to a car that reacts blindingly fast, whatever request the driver hands down." Until the 2010 model year, BMW M has also never used supercharging or turbocharging, unlike Mercedes-AMG or Audi; for instance the E39 and E60 iterations of the BMW M5 (using naturally-aspirated engines) competed against the Mercedes-Benz E55 AMG (with a supercharged V8) and the Audi RS6 (twin-turbo). BMW M vehicles typically use manual and automatic transmissions (the most recent type being a dual-clutch transmission), in contrast to Mercedes-AMG which largely has automatic transmissions (the 7-speed AMG SpeedShift MCT, which is a multi-clutch automatic transmission, but not a dual-clutch transmission, was used on new models from 2009 onward). However, the North American market E36 M3s in sedan and convertible form were the first M-vehicles offered with a traditional torque-converter automatic transmission. BMW M engines were traditionally large displacement naturally aspirated high revving engines, particularly the S85 V10 in the E60 M5 and E63 M6 and the related S65