We use Keis heated jackets, these are very toasty, you never need them on the maximum setting in the M3W.
Great post Rog G
Keis are fantastic & I've got the vest I use on the m/cycle - Milwaukee make a jacket too but the seat mod is where I feel I want to be, especially in reducing the pre drive prep time and messing around with chargers - I've also seen heated cushions on eBay which are really cheap but I think heated seats 4 me