To explain:
1) DRZ 400 E - Sold as an enduro bike, not road legal. The first choice of many because this version comes with slightly more power. The extra power is a result of; a superior carburettor, higher lift cams, and a different base gasket resulting in a higher compression ratio.
2) DRZ 400 S - The dual purpose version. Completely road legal with off road ability. Slightly less power than the 'E' but no need to mess around making it road legal.
3) DRZ 400 SM - The supermoto version. As the 'S' but with 17" road wheels and tyres, uprated brakes and upside down forks.