I’ve always tried to speed faster when flying at cruising altitude, but I’ve always got speed violations. Is this person not getting violations?
What you’re seeing is that users ground speed, which is usually quite higher than your air speed at cruising altitude.
I recommend you have a look through the guides in #tutorials to get you acquainted with how everything about that works :)
So is he really going about 350 kts?
Probably slower actually. It all depends on what the winds are etc. I flew in that area not long ago and had a 100kts+ tail wind…