I have 3 R11's and just ordered a 2017 US Kit for carpet as well. Cant wait to get this thing out for its first run. Everything else has been exceptional as far as quality, part fitment, and out of the box, they are definitely a force to be reckoned with. Now I just need the driver to get better, but I can tell you, that these cars make it so much easier to drive and improve.
Lots of support on the Facebook ARC team pages, both here in the US and Europe/Asia. Very helpful team members and lots of setups on PetitRC