The dealer in Idaho Falls did the official factory lowering work on my 2009 DR650SE. Just enough that the suspension would sag and allow me to get both feet flat. The 2015 I just acquired is stock height, so I'm just getting toes down. The rear link requires just ordinary tools. Pulling the spacer from the fork tubes requires a special tool to unscrew a retainer. I could probably do it myself, but not with ambient temperatures at +25F.
Do you recall about how much they charged for lowering it?