MAke sure you check the balance of your tire on the corner with the leaking shock. I had my right rear shock replced under warranty as it developed a pretty good leak. At the Rally in Vegas on the Valley of Fire drive, I first noticed a vibration when the speeds were , well, uh, slightly above the posted limits. Upon inspection, I noticed the leaking shock.
Just for kicks, I put the wheel/tire on the balancer and it was WAY off. I mean, way off. This was really strange. I have had the car since new. The tire had never been off of that rim and the OEM weights were still in place. I can't help but wonder if at some point or another if the tire rotated slightly on that rim.
However it happened, I believe that the rather severe (but hardly noticeable in-cabin) tire imbalance caused that shock to wear prematurely.
Long story short - check the balance.