The K20Z3 is an excellent motor, extremely well built and reliable! You might have some 3rd gear grind transmission issues in addition to the regular wear and tear (plastic seals ect.), but with regular maintenance you should easily be able to get 200k miles out of it.
When I rebuilt my engine 2 years ago the crank bearings looked brand new, the valve seals however were showing sign of wear it looked like it was starting to leak some oil. You'll probably need to do a cylinder head rebuild before you touch the crank/bottom end.