I have considered the same thing but eventually gave up on the idea. It seems there are no decent parts available for doing this and the arm was not really designed to be done like that but rather to be purchased as a complete assembly. Even if you find decent parts now, you might not find them 5 years down the road when trying to do it again. The OE arm works fine in normal driving but some on the market are coming out of China. Most people stay with those made by Moog, it is a better and heavier unit.
I thought I could save a few $ buy re-building my original arms but when I considered that I only cover 2000 to 4000 miles per year, I figured I would never wearout the new ones, so I just bought the complete arms.