You might be able to find complete strut assemblies online, which would save you much time and doubt- if your spring is done, chances are the rest of the unit is too. Amazon, eBay, Partsgeek are good sources. If you buy from your local national chain store, they'll loan you the tools, or you can buy a spring compressor for $35 or so. Follow instructions in your manual, and be VERY careful once the damper nut and upper mount are off! And yes, you do need to replace both sides!
Gritmonkey
July 2013