I dont understand why hasnt anyone used an Engine Torque strap or a torque limiter to prevent the engine from twisting and popping its motor mounts.
The racing community has been doing this for years. It can be as simple as a piece of chain bolted to an accesory bracket on the engine and bolted to the frame or something significant to prevent the engine from excessive twisting.
The also offer kits with a rachet type tie down that hooks to the motor and bolts to the frame and you can adjust the tension. All for like $30.. A little easier than changing motor mounts.
Majority of failures were due to front wheel spin and suddenly tire catching traction. Instead of popping a CV joint, hub, it takes out a motor mount.
Just an idea. I am dealing with the same issue on my Grand National, and there are solutions already out there. Why re-invent the wheel. Its an old problem that came before the Xterra.