The term "Intake Slide" is new to me but due to the price I presume they are talking about the Throttle Assy or throttle Actuator.
On your car you probably have ASR. If so you also have EA (electronic accelerator). This is basically drive by wire (although there is real wire (cable) to back it up. When MB went to EA it made it real easy to incorporate CC and ISC within (Cruise Control and Idle Speed Control). The earlier forms of idle speed control used a separate intake mechanism for air flow at idle called an air slide. It was called that because instead of acting as a throttle (a rotating flat plate in a round bore), it placed a sideways slide to control the airflow. I presume that someone has combined the terms not knowing where they come from.
Anyway, the throttle assy is a gathering of motor/gearings and electronics that allow precise positioning of the throttle plate. This was a common problem in those cars. The replacement is a redesigned part and the previous failure bears no significance to furure problems (IMHO).
Bosch Master, ASE Master, L1
33 years MB technician