http://help.solidworks.com/2011/Engl...irror_Part.htm is a Solidworks tutorial on creating a Mirror Part. I've done this once or twice, although I seem to remember having some difficulty with the process... Not sure, though, so you could try that.
All I can think of in terms of parameters is equation driven dimensions that act off of global variables shown in the hierarchy tree. It's been a while since I've played with that, and I don't currently have Solidworks installed, so sorry I can't give a more detailed walkthrough. Somehow you create a global variable, and then when you smart dimension something there is the option to make a new equation for that dimension. You might have to look around a bit.
Hope that helps. Hopefully someone else comes along and knows a bit more about those specific features.