I have researched forums and YouTube for help removing the grill on my 2003 SL55 to no avail. They all show releasing two lower tabs located left and right. I believe those are released but it seems to be locked in the center. I have moved the grill left, right, up, down, pushed and pulled with no change. I cannot see that area from above and the lower edge fits tightly against the bumper cover. I am trying to access the ABC heat exchanger. Thank you for your help.

 

I decided that the correct way to remove the grille on this model is to rotate it forward and down. It is supposed to be very easy. Mine was difficult, apparently due to 22 years of dirt, heat, and water that resulted in it sticking. Part of a tab broke when forced.

 

Slide it back an inch or so at the bottom IIRC.

Spray a little silicone spray in all the crevices when disassembling old parts like this.

Glue back the broken tabs with cyanoacrylate and baking soda.