Actually 6 washers and 4 shocks!!
My girl and I got done putting our 2" Budget Boost on and some 10,000lb tow hooks. Stock shocks still in use as the new ones are in route. Looks great but even after adding 3/8" worth of washers to my belly pan I still have a slight bit of driveline vibration. Fortunatley adding more is a piece of cake. Wrangler Forum was a huge help in our latest venture.