Regarding the MPG, I just ran out and checked.  It's 18.6 off the dash.  As for the death wobble, for 2019, I couldn't take the Jeep home because of the factory recall of the steering stabilizer.  It was "upgraded".  Now as for top speed, I hadn't brought it into triple digits, but it does 85- 90 with no issue.  Closed roads of course.  This is with 7000 miles on the ODO.  Personally, I love it. YMMV.
L J