Hello Subie friends, recently been on highway, speed limit 80mph, seems a vibation occurs around 63 to 67mph goes away, then comes in strong around 70mph. Thinking about replacing all hub bearings or whatever is suggested, if any. Thank you.

Tire balance is likely the cause.

I'd start with that. It's fairly cheap to have it done anyways.

Could be axles or anything drivetrain related. But typically it's a balance issue.

Thanks, hopping it's tires, they are new, should have mentioned it's 6 lug conversion, with Toyota alloys. Tires are a low grade from Swab, just the size they had when I came in.

Vibration frequency?  below even the lowest bass notes?  or can you hear it?

Drive shaft U joints I've had make a low note vibration at highway speeds.  Wheels / tires out of balance, more of something you just feel.