When aiming your lights, have your engine running since your SL
has ADS suspension and will need to be level. When running and with the headlights on, they should be adjusted automaticly by the HRA (head lamp range adjustment) system. if you need to adjust them further, It can be done with the 13mm plastic adjuster nut/wheels on the rear of the lamp units. it is just like a car with halogens in that reguard. Try to heep them low, 129's are viscious to look at when their xenons are too high. Yikes!
Good luck
DR.D