Outer Limits 4x4 Board

My mate just bought a 89 2.4p 4runner. Looks and drives like its in pretty good nick. Just had its head replaced. No slack in the drive line. Running 31x10.5.
Q - Just wondering what common problems/weaknesses etc or other faults and quirks this model of 4runner have.

It is pretty stock styandard.

He will appriciate all your help alot.
I feel helpless as i don't know 4runners that well...
Cheers guys.

Front diff strength as it uses a smaller/thinner crown wheel than the solid front end models, and if you dont monitor the CV boot condition you will grind these out aswell..

Other than that, i have an 86 Diesel model, apart from the IFS its quite a good car to start of with