I too agree that AMG wheels are not light, whereas the CLK wheels are.
Split rims were originally for racing teams so they could find what size and offset worked best before committing to lightweight versions. They are really bad to use as they weigh more and the mass is right at the rim, so has a greater gyroscopic effect.
Name| Manufacturing Method| Size | Weight (lbs.)| Weight (kgs.)
Mercedes Benz AMG SLK (Front)| Forged| 17x7.5| 22.8| 10.3|
Mercedes Benz AMG SLK (Rear)| Forged| 17x8.5| 23.6 |10.7|
Mercedes Benz C32 (Front)| Cast| 17x7.5| 25.6| 11.6|
Mercedes Benz C32 (Rear)| Cast| 17x8.5| 26| 11.7|
Mercedes Benz C55 (Front)| Forged| 18x8.5| 26.4| 11.9|
Mercedes Benz C55 (Rear)| Forged| 18x9.5| 27.2| 12.3|
Mercedes Benz C7 Sport (W203)| Cast| 17x7.5| 24.6| 11.1|
Mercedes Benz CLK230 98-99| Forged| 16x7| 12.9| 5.8|
Mercedes Benz E-Class W124 (EVO II)| Forged| 18x8.5| 24.7 |11.2|
Mercedes Benz E-Class W124 (15 Hole)| Cast| 15x6.5| 17.9| 8.1|
Mercedes Benz E-Class W124 (8 Hole)| Cast| 15x6.5| 19.6| 8.8|
Mercedes Benz E-Class W124 (8 Hole)| Cast| 16x8| 23.2| 10.5|
Mercedes Benz CLK320 (6 Spoke)| Forged| 16x7| 14.5| 6.5|
Mercedes Benz SL600 (1997)| Forged| 18x8.5| 25.5| 11.5|
Mercedes Benz SL600 (1997)| Forged| 18x9.5| 26.5 |12.0