It would help to know where the "smoke" is coming from and what it looks or smells like. For example, white smoke from the engine compartment after a recent oil change could just be burning oil that spilled on your engine or pipes. Smoke from under the car with an acrid sweet smell could suggest problems with your transmission. Generally speaking smoke means something is overheating, so try and determine the area of the car from which the smoke is coming. Check all your fluid levels and make sure you're not running your car low on oil or other vital fluids.
yes the BMW M3 has a V6 but it can have a V8
The 2008 BMW M3 has a V8 engine.
The 2001 BMW M5 has a V8 engine.
The 2012 BMW M3 has a V8 engine.
The 2013 BMW M5 has a V8 engine.
The 2003 BMW M5 has a V8 engine.
The 2010 BMW M3 has a V8 engine.
The 2014 BMW M6 has a V8 engine.
The 2002 BMW M5 has a V8 engine.
The 2011 BMW M3 has a V8 engine.
The 2014 BMW M5 has a V8 engine.
The 2013 BMW M6 has a V8 engine.