I thought the 2D sensor was built in on the 2015s
I did install one on my HP4. seems to work and it is plug and play. need to keep an eye on it because it is somewhat delicate looking. As I understand if you get a 2015 with DDC the 2D sensor for the forks is built in and there are more selections for adjustments over the HP4.
As far as we can tell, the 2d sensor is still available for purchase separately for the 2015 models, but that may not denote that the 2015 does not come equipped with it. Sorry about the delayed response, but Brad isn't here anymore and I'm playing catch up. Still learning the ins and outs of the new bike, but I'll try to get a definitive answer and post up as soon as I know for sure.