at 138K your control arms (the ball joint is embedded in them) need to be replaced most likely. I would do the tie rod ends at the same time since you will need an alignment. Don't forget the sway bar links, they go every 30K or so and cause rattling type feeling/sound. BTW, are you sure about your rotors? the can look like new, but have even the most slight warp and you will feel it when you brake, particularily at higher speeds. Volvo rotors warp very easily, especially if they have EVER been turned/resurfaced. For supsension parts, I always use genuine and not that scan-tech stuff cause it doesn't seem to last as long.

at that mileage you will have play in your steering rack, but that should only cause play in the steering wheel, not vibration.