When I did the PCV service on my S70 T5 a few months back, I used the PFV oil separator box and small hoses, with a genuine Volvo camshaft breather pipe, and did the 5/8in heater hose mod (
https://www.matthewsvolvosite.com/fo...ic.php?t=53448). I used 5mm ID silicon hose for the other pipes.
All working fine, and the PCV oil box seemed to be of a decent quality.