Inventor 2011 - Parameter Linking

[Smrtman5]

Does anyone create linked parts / iparts on a regular basis? My motivation for doing this is creating many similar part ie a valve in 1/2-2" sizes with the same design but scaled dimensions.

Im still new to this method so i havnt figured out exactly how to do it. Is it much easier than the 'save as' method? What are some advantages and disavantages?

Thanks