Yeah not terrible, but I picked up a pair of fender flares for mine. Going to install them this weekend. They definitely stick out enough to chuck some big rocks at the side mirrors, lol.
Exact height could vary depending on wheel width and how much air you run in the tire. I can tell you with a 6" Lift and 35's I clear my garage just fine with a 7ft door.
I will try and get a good picture this afternoon when the rain clears out. I did measure and they stick out 2.75" from the body. If I had it all to do over again I would go with 20x9 wheels and 5" backspace. This should prevent it from rubbing like mine does on the back side of the outer fender. I had to do some trimming on the metal for fitment.
The only thing they had a possible release date was the 5" kit. I'm assuming they would develop a 3.5" kit like there others that would be compatible. They have online chat and are quick to reply.
New to the forums here but I've been watching this thread. I love the look of the Fabtech 4" kit and have been close to ordering one for my 16 Denali. I was on chat today with Rough Country after seeing the video of a 15 Denali running the 5" kit. They are saying they have a magnetic ride kit coming out in the next 1-2 weeks. So now comes the fun part of should I wait on the 5" kit.