VPI 300 RPM vs 600 RPM Better?

The 300rpm motor is not necessarily a better motor than the 600rpm as proven by the fact that many vpi users are split between the two. Many users cannot discern a difference between the two. Yes, motors do take time to break in.

The only purpose a motor serves is to maintain the correct speed of the turn table. It is out of the signal path. So I suggest you check the TT speed to make sure it is correct and stable.

Another way a motor can affect sound is the motor vibration transmitted to the turn table. That is the basics for the 300rpm motor upgrade because it is spinning at lower speed and vibrates less than the 600rpm one. So if the motor isn't quiet enough, you might want put a drop of motor oil in to quiet it down. The user manual has details on what oil to use and where to put it.

I think you will get better result with this approach than relying on some mysterious break in process.

No, it is just another way for Harry to make money, bless his heart. Harry is a master at the game of 'new', when nothing has really changed in ten years.

Silly me, I thought the 600 rpm motor was the upgrade???