LED additional headlights on the W463

Hello, because the xenon light on the G is not really good, I would like to retrofit a few additional lights in LED technology, for example Hella Luminator X LED. So far so good. However, there are questions that I cannot answer without a doubt in the net. – Up to what reference number can I install additional lights? The standard number has a reference number of 20. If I understand the guideline correctly, I now have to add 2 x 20. 100 is the maximum reference number for a car after 2009 => i.e. 60 are still free, i.e. max. 2 x 30? But there are no LED additional headlights below 37,5 per lamp … very confusing – How and where did you attach your additional headlights? I would like to drill very reluctantly into the bumper. I think of a fastening behind the black “mark plate”. Or there are fixed points at work. For advice and suggestions I am very grateful. With best greeting TMD