I bought a new-old-stock B044414 TPS from eBay and replaced it myself. It wasn't that difficult, I was very careful to not damage any cables and took lot's of photos during removal which made it much easier to re-install. The most difficult part was removing and re-installing the two throttle cables to the TPS. The whole job took a couple hours. Afterwards you need to do Handle Learning then Throttle Learning (in that order). You will need the cables and Guzzidiag to do that.
There's a video of a guy replacing the demand sensor and checking/calibrating using Diag on YouTube (it's in German though, but you get the gist of it and Google Translate or other dictionary be used to translate specific words). The Workshop manual also gives you suggested voltage for the 4 tracks A-D if you think there might be a problem.
I sometimes wonder if this guy ever gets to ride his bike as he's always taking it apart to make videos (glad he does though)