Questions from a beginner

[MPoore10]

I have read the archives and have learned quite a bit from all of your posts.
My area of specialty is in the engine mechanicals and performance minded
engine building. As far as the latter goes, I have discovered that I can't get
the most from an engine by ignoring the ecm/eprom or relying on someone in
another state to send me a generic performance eprom. 
To that end, I am really interested in getting into the programming aspects of
the eprom. Specifically, I would like to be able to create my own eproms. I
have read about MasterTune software. Is this my best bet? If you have
experience with that software could you please relate your experience with it
and how useful it would be? I really don't have a great deal of time or
interest to do my own code breaking. And I don't want to repeat work that has
already been done. Or is there other software that would work better for me?
Ideally, I would like something that I could download the OEM eprom data,
emulate the eprom with my PC while I tweak it, and then burn a new eprom after
optimizing the data for the application. Is such a setup available as a
package? Or, would I have to build it myself? After reading the archives, I
assume that manufacturers don't release information on their eproms as to what
it contains and where it is on the chip. So, is it every man for himself on
code breaking or is there a place to go and get this infromation?

Please e-mail me direct with your comments. Thanks in advance for any insight
you can provide.

Mike