This is the kit that I used.
Heated Grip
I never bothered with the included High/low switch. I ran the on/off switch to my police switch. I turn it on when my hands are cold and after a couple minutes I shut them off. They stay nice and warm for a while before I switch it back on. Be sure to wire them up through a relay and you should be good to go. Actualy if you go with the factory switch you can probably get by with letting it take the load. It is up to you.
If you are careful you may be able to reuse your grips or use a set of BMW grips. Most people like them.
One word of advice for you is that if you use the grips heaters like this is to add some electrical tape to the bare bar on the left grip. If you don't it won't heat up as much as the right. The right grip is on a plastic sleave so it is insulated a little bit from the cold bars. The other option is to use a resitor on the right grip but that would limit your heat output a little.
Your other option is heated gloves. May will point out this is better because even with heated grips only the palm of your hand is heated. With heated gloves the back of your hand and fingers are warmed.