not the tensioner pulley
X50 famous for alternator pulley issue lately, but their case is the pulley become loose and cannot charge battery
for S70, I dunno yet

in my case, my belt screeching (not S70), send to diagnose, is not belt or tensioner issue, but because alternator pulley jam
- when idle, aircon off, masuk gear - vibrate
- when idle, aircon on and compressor running, masuk gear - screeching noise and vibrate

then my x50 probably different issue.
when AC on, idle the engine/stop car. something screeching,
turn AC off, idle the engine/stop car, more loud it screeching.
but when you AC on or off while moving, with some RPM there...less screeching or not auditable due to engine noise.
now narrowed down to all kind of pulley+belt...yet pulling it out to check one by one...
my alternator/battery charge seem ok

oh like this... probably tensioner bearing or those things
I'm not familiar with X50 structure, but should easily diagnose and replace it

Any comfort and cheap tyres recommended for s70?

Wah original so fast worn out? Whats your mileage

Not worn out. More like wanna change to a more quiet tyres.