HSP it was pretty straightforward. I was messing around with HIDs and oil change at the same time so I can not say how long it took. Once the fairing is off just unplug the air temp gauge, twist the bezel and out it comes. On the oil pan, just to the right of the engine oil drain plug is another plug, remove that and place in the the one from the kit with the temp sensor. Hardest part is zip tying wire harness to frame so it looks nice (Big fingers, little spaces).
Here's a plug for the HD service manual. It is very handy to have. I was looking all over for the air temp sensor thinking it had to be some place other than in the speedo housing. But a check in the appendix for sensor locations and it tells you right there where to go.
As far as selling the air temp gauge, my conscious wouldn't allow me to benefit monetarily by continuing it's uselessness in this world. I'd rather encourage the buyer to just get the oil temp kit.