I didn't run so much my XX4 but I already break a chassis on the front end, on one of the two "ears" which hold thread inserts for mounting the front bulkhead
I don't know if someone had already done the mod I made, but here it is described below.
So on a new chassis I decided to modify it by drilling two additional hole in order to insert longer front arm hinge pin in the bulkhead.
First mod, I used two old 1.2" rear shock shafts where I cut the threaded tips. On the following picture, one is cut and one is still uncut)
Then with an 1/8" drill bit through the bulkhead I drilled the chassis:
Here are some pictures with long hinge pins in place:
Hope now it will prevent any ear breakage. I suppose I will break more front arms due to rigidify the the bulkhead but arms are less expensive than chassis and much more easy to replace than chassis....
Just my two cents