Legacy specB rear noise
 

Test drove a 3litre specb 2004 legacy, nice car but there was a noise from the rear that concerned me, it sounded like a wheel bearing going, but could it also be the rear diff.
If the diff, is this a game changer due to costs, or quite easy to fix/replace.

Diff issues are fairly uncommon on the legacy. But wheel bearing failures are much more likely. If it's the diff then one from a breaker could be £250, plus a few hours labour to fit. But it's worth getting it inspected.