To be honest, I can't remember the claimed output, but it is kind of irrelevant as it's quoted at a specific engine speed and if you're running slower you'll have less available and vice versa.
Yes, you can run heated clothing and heated grips etc, but I would make some recommendations, in order of priority:
1 - FIT A VOLTMETER. Sorry to shout, but this is the best way to see whether you are exceeding the capability of the stator at any given precise moment in time. If the voltage of the system is maintaining at 13.5 volts or more, you're charging the battery and not risking any problems. If it's 12.7 or less for any significant time, you'll be discharging whilst the voltage is low and if there's no sign of being able to up the engine speed (you're stuck in traffic, or doing some gnarly off road section) then you should switch stuff off until the voltage looks healthier.
2 - Fit a switch to dipped beam. Don't turn it off at night or on the motorway or anything, but out in the wilds, this could be a useful way to free up some power for something else
3 - make your own heated clothing - that way you can tailor the power consumption to the bike. The zip-out liner to the riding jacket I took to Siberia and back is now a 60W heated vest, courtesy of a little home-tinkering. DRZ coped with that and Oxford Hot-Grips just fine.
4 - if you've not got a DRZ yet, buy mine
(ultimate-overlanding-drz for sale
'02 Africa Twin (sold), GSX-R 1000 K5 (sold), '97 TL1000S, '08 DRZ400 SM/S, '92 CRM250