Personally my xj is already 25+ years old. I'm plating and stuff but at some point the unibody/frame will come apart. Ether crack or just start failing, especially with how its driven. At that point ill be building an older square burb, 35s with a 60/14ff. Hopefully a diesel. I don't NEED the burb but pulling the 3rd row seats gives me sleeping room and its a freaking tank, 35s would be enough &0 tons that'll live through just about anything.
Fwiw my buddy Chris shaved his 14ff and gained something like 3" below the diff, I'd deffinetly look into that lol.