(P/n is 64112964044), cost about £145, with a separate non-integrated controller.
The big advantage of the KTM part is the simplicity of the throttle install as the grip come with its own throttle tube installed, which is the most complex part of the install with aftermarket solutions. To install the new grips you only have to remove three screws. However the selection is not sticky, once ignition is turned off, the grips are turned off as well.
To install on the left side roll the factory rubber grip back: on the bottom there is a set screw. Remove and slide the entire grip off. Reverse the operation to install the left side heated grip.
For the right side remove the throttle tube system from the bike by unscrewing the 2 Phillips screws from the throttle sensor/housing. The throttle tube slides right off. Slip the right heated grip in place, put the screws back in and you are done.
The rest of the install is simple: install the controller, wire it to the ACC power in the headlight.
Despite the easy install the result is not well integrated with the bike, with an ugly controller. You might want to consider non KTM options, and go with the grips you like. Below you can find the steps to install the Koso Apollo grips (also known as Technoglobe Gold) which are good. Make sure to get the 130mm version.
There is discussion as the exact diameter of those grips. The two installs used to write this FAQ entry disagree on the sizes! One states that they are slimmer than the original grip. The other claims that the same grips are thicker! I guess more that one versions of those grips exists, hence the discrepancy?
The difficulty of the install is all due to the throttle tube. It is not available as a separate part from KTM, so you need to figure a way to unglue the rubber from the plastic tube and then file it clean.
One way is to scrap it off with a blade, it’s long and dirty, but works:
Another option is to make a slit on the whole length of the rubber and skin it off
It should also be possible to heat it up a bit with a heat gun, slid a screwdriver in between the grip and the plastic, inject some WD40 and break the bond by going around with the screwdriver, but the tabs might get on the way, see below.
Once the rubber is removed from the tube, you need to remove the tabs there with a blade as they will prevent the new rubber to slip in place. They are pointed out in this picture. Note the inner hump next to the sensor housing: removing it makes for a snug fit without a strange gap between the housing and the grip. The fit is PERFECT but you only have one try since the fit is so tight.
Once the tube is clean, put the new grips on. On the throttle side pay attention to the position of the wire on the throttle tube as to not limit the range of motion. Check 3 times before doing it.
The rest is easier, just decide if you want to connect to the accessory connector under the seat or in the headlight. The headlight is closer, and easy to open despite the numerous screws. Make sure to fix all the wires and the small controller to not be in the way of any moving parts.
See the entry on power to locate the accessory connectors.