2004RennTechE55

About 2 or 3 weeks ago my right front air shock failed on my 2004 e55. I could hear air coming out of it. I put off ordering the part until I had more cash and free time to do the job myself. Well I just ordered the front right shock and went out to look at my beast and now it seems the right rear just failed today. Is there something else that might be wrong here? Should I just eat my pride and call the dealership or should I just buy the right rear shock and do both at once? If anyone has gone the coil over rout, please add your 2 cents as well.