gomez,
Some gunslingers will take an oppo or low end denon and send it to a special electronic shop to replace internal parts like master clock/DAC to a higher grade. The result is a better sounding unit.

I thought it was hype. But if you do a little research - you will find information on different types of jitter and its affects on the digital signal. This is more than audio sound - but digital communication.

Essentially - when you buy more expensive transports/players - (in theory) you are buying better components designed: to minimize jitter, to control power distribution (digital) and other internal interferences associated w/ jitter.