I jave a '93 non-SR5 Xt-cab sitting in my driveway.
It has the split-bench seat, which BTW is really cool IMO - all the advantages to seperate bucket seats, but the option of a 3rd person (see sweethaert comment above!) or sleeping in the cabin (well as long as you aren't 6' tall).

It also has sliding open rear glass and tilt steering. The guages include a tach and voltmeeter, can't imagine whatmore youcould want?

My 88 4Runner is a DLX, aparently it came with NOTHING fancy at all.
In looking into this previouslt, I found that 100% of the SR5 stuff could be swapped in w/ minimal effort, i did most of it at various times.
IMO the best upgrade is the variable intermitant wipers, but I think all the 3rd gen vehicles have that?