Jeep: Keep 89 or go 97 or higher

I have an 89 YJ Sahara 136,000 mile I have had for the last 6 years.
Pretty clean with no real problems and pretty much stock. I am
considering giving it a bit of an overhaul and getting bigger
tires/wheels and tricking it out a bit. Figuring on spending a few
grand or so...

Question is if this is a smart decision or am I better off looking for
a later model ala 97-99?

Any thoughts?