If you need to add length, make sure you know what wire size you're dealing with. These are all metric wires (specified in mm2, not AWG). https://www.prysmiangroup.com/sites/default/files/atoms/files/Automotive_Catalog%20new%2023.11.15.pdf is a good reference for measuring the OD of the wires to estimate the conductor size before you cut. The "FLR21X-B hffr" spec wire is similar or the same as what MB uses (it's "approved by Daimler"), and the ODs I measured line up almost perfectly with what is in this catalog. Metric size wire isn't readily available here, so just convert mm2 to AWG. "TXL" spec wire (SAE J1128) matches closest to the MB vehicle wire that can be easily found in the US, but the thicker insulation "GXL" version should work too.