"wringing the neck" is a nice way to put it with the WRR. I rode my partners DRZ400 several times when I was making the decision between the WR and the DRZ. There is definitely more grunt there with the bigger bore and more horses. In the end, it was the fuel injection (I hate fiddling with carbs) and the 6th gear that pushed me over the edge to the WRR. But i still liek that DRZ. To be honest, I am sure someone way more talented than I could see a tangible difference, but after riding off-trail in the dirt with my buddy the way we normally ride - I see little to no difference between the two. We keep up with each other just fine - albeit I am likely running higher RPMs than the DRZ. But once back on the tarmac, the DRZ has more legs for sure.
Enjoy the little bike!! I find that the addition of a little bike has been an invaluable tool in helping me develop and hone dirt skills that I can then transfer to the SuperTen.