According to Joe's differences thread, 1999 up have a 460 watt stator.
Take away two 35 watt head lights, 2, 10 watt running lamps, two 15 watt tail lamps, and guessing 170 watts or so for injectors and instruments leaves another 170 watts or 14 amps from a stator at full output.
The GPS, passport, and Ipod probably don't pull 5 watts combined. But heated gear is power hungry.
If my guess on the systems power consumption is close, you only have 160 watts to run the heated stuff. What is the rating on the grips and vest?