At 150k, it is time to do the chain, guides and tensioner, if it hasn't already been done.

The engine should be pretty quiet, if you hear excessive grinding coming from the valve covers, stay away. Let it idle and look for blue smoke (valve guides). If there is a miss or stumble at hot idle it is probably a spark plug or two fouled from bad valve guides.

Drive the car easy and hard and see how it shifts in both situations.

Other than that, nothing to really look for. Good luck.