The install doesn't involve anything crazy or complicated, but the instructions are convoluted and could be greatly simplified.
Removal of the stock hardware is easy. DP Brake install is a breeze.
For the shift side, ignore the instructions when removing the shift rod. The instructions say to unbolt the rod completely from the bike, which requires removal of the slave cylinder to get access to the bolt holding it on. Completely not necessary. After removing the stock rearset remove the stock shift rod simply by using a 17mm open ended wrench on the left (fore) side of the rod (to hold it in place) and a 12mm on the back end to loosen. It's not reverse threaded, like some linkages, but it's loctited, so don't be surprised if it takes more effort than you think.
Then you just need to figure out which size replacement rod is needed. There are several options--high or low footpeg setting and standard or GP shift. There's a chart, so just figure out what you're going to be running and pick the right one, install, then bolt on the rearset and adjust.
Note--the DP rearsets come with both the GP and the standard shift linkages installed. The one you don't want has to be removed. If you leave both on you won't be able to shift. The instructions said nothing directly about this--at least not on the pages I paid any attention to.
In short, if you're pretty good with a wrench and have basic understanding of how things work it's a 2/5 on the difficulty scale. If you've only installed turn signals and still say, 'lefty loosey' when taking your bodywork off, it's going to be overwhelming, but you'll get through it...probably.
Just make sure you loctite and/or grease what needs to be loctited and/or greased--and make sure it's all torqued down properly. Rearset bolts tend to be the first to go....