I recently bought a 2006 V50 T5 AWD. So far it's been great, despite having to replace the tires and get an alignment after purchase. The old ones were bald on the outside edge. Also the driver's side rear tire was different from the other three. I'm a tad worried about how long it had been that way and what it's done to the AWD system.
However my most pressing concern right now is what this noise is coming from the engine. I'm not new to the P1 or the T5, my Dad owns a 2013 C70 T5, so I'm fairly familiar with what sounds the engine should be making.
Here's a youtube video showing the noise. I've adjusted the gain and eq of the audio so that this high pitched whine can be more clearly heard, although I think youtube lowered the volume, sorry.