save the money and invest in some heated gear. being a beemer rider too. a great investment was a heated vest. i am able to ride in 20* air temps w/out that lower back cold feeling.
too bad HD can't produce a heated grip like BMW. that was worth its weight in Cold !
Tgaetto is right, I would put some $$ into heated riding gear, like that offered by Gerbing, it really works well and I bet it will outlast a HD heated seat by years. Plus if you have or ever have the luxury of having more than one bike you can take the heat where ever you go.
I live in CA....Heated riding gear would not get used too often. I ride to te low 50s/ upper 40s with no heated gear. I'm only thinking it would be good for my back...the seat in my cage was awesome.
I don't know if a heated bike seat will provide the same back therapy as a heated car/truck seat. I would think a bike seat would just heat very bottom of your butt and hammy's. A car seat tends to heat that, plus the small of you back. At least the ones in my truck do. I admit, I have never used a heated bike seat. Have you thought of using those stick on heat patches for your back on longer rides?
does yer butt get cold? for me a heated vest does enuf. with the kidney belt tightend up i get lotsa heat to my lower back. did 45 min in -1F the other day in a t-shirt my heated vest and fxrg jacket and all was good