AIRSPRINGS SHOULD I CHANGE R-SIDE BOTH SIDES?AS R-SIDE USED TO SAGE NOT ANY MORE

It might be like replacing a pair of shoes rather than replacing just one shoe. If one side was sagging for a long time it could in theory have weakened the other side but if there was no duplication in labor to do one side and address the other side later if it gives trouble. My head says replace both sides at once if one side failed the other may not be far behind but my wallet would say replace one side. Ask the advice of the Mercedes specialist working on the car, if he works on these cars all the time he will be best able to advice you. Ask him what would he do if it was his own car. I forgot to ask is there a Bilstien conversion kit like what is available to fully convert the suspension away from air bags (they make kits for Jaguar and Range Rover.