No it is not necessary, but every install nets a different result. We wanted to add the heavy duty parts and have the adjustability, and now I am glad we did. Just make sure you have a shop that has done a bunch of clutches do yours, preferably a shop that knows the SN95. They will likely be more apt to get you what you want.
A lot of people rave over the Centerforce dual friction or Mcleod dual friction...these are a couple other very popular choices you may want to look at as well. You'll need to have the flywheel resurfaced, but this is a normal part of replacing the clutch (hopefully...dbl ck to make sure they are resurfacing it!). Also, be sure a good TOB bearing is also installed.