Your friend, and Tony and I say Tie Rod Ends, at least.

You can get away with deferring the replacement for a bit. Depends on the driving requirements. Under 45mph, easy traffic. Maybe OK. Over 45, things can get wacky and make bad things happen fast.

If you experience the vibration and a small steer to either the right or the left ends it, that's a good clue for TRE's. Sometimes the other steering or suspension elements go bad, too. The 3/9 slack is really good, especially if the wheel is turned to one side (to the right to see the RH TRE) so you can look at the TRE and see it move.

Inner tie rod joints (part of the tie rod itself), ball joints, etc. At any rate, when any of those are replaced a new front end alignment is required. There's a bit of savings when one replaces all those elements, maybe rear arm bushings, too, and gets just the one alignment.

Good Luck,

Bob

:>)