I have a 245/75 MTR on OE Limited wheels and the glass is not an issue
the bumper was an issue washers fixed that
also no sag after about 2 years and my wife ,really her ride, uses it for a DD and is in and out of it all the time
we have a 1 year old baby and she does some out side sales work

now the TJ is another story when it comes to sag
let me just say this you have to push it harder now

also just remember that when the gate is closed there is much less stress on it then when it is open
so if you are carrying 3 bikes on the MTR ,like I have done, remove them before you open the gate