Hi, there. As far as your oil pressure you should be ok. In my car it will sit at about 20 but is goes up when the car starts going witch is what you want to see. In the manual for MBZ it lists that during idle the pressure can drop as low as 04 but I never seen it that low. As far as oil leak you need to clean the underside and find out as to where is the leak originating, then you can decide do you want to tackle this job or take it to the shop. All the MBZ leak oil it's the charm of the car......