Good question and glad it was asked. File sharing is fine, but if a
tune were identified as being intellectual property of a third party,
created by other than the party posting it, it would have to be
removed. Court tested, Napster comes to mind, no different really.

However, what is done non-publicly reaches into your own comfort level
with the knowns. I have personally looked at all the majot players in
the diesel tuning market. I have found that none of them meet my
criteria for a decent tune: none of them reach into the core of the
stock tune that makes it less than desirable as refinement goes. It
begins with a very loud and laborious reality...you must begin with a
new fuel pressure table. None of the tuning companies do this, as it
represents a real R&D process, it becomes a very long process but as
far as I am concerned, worth the added effort.