So much of this post reeks with "former, disgruntled employee", what's left is just flat out lies. So while I won't touch your rants and ravings with a 10 foot pole, let me clear up your rumors and lies.
The motor in 5300s is the exact same motor used in 7500 and Professional 750. There is no "inferior" motor.
The pad you're referencing only fits the 5200 model and covers up the air vents. Noise from Vitamix machines largely comes from two things: contents of the container, and air flow. Sure, by plugging up the vents, the machine will be quieter... and since there's no air flow, it'll also overheat.