Since the real OE wires are just that, solid stranded wire, there isn't any resistance drop like American cars. But the spark plug ends are the resistors. There have been 3 different values over the years 1K, 2K, & 5K ohms. At the coil there is usually a 1K ohm resistor. Most of the Bosch aftermarket stuff is Stranded cloth like american junk. The wires (OE copper) themselves rarely go bad but the resistor ends fail & can be replaced by themselves. Beru replacements are OE quality with solid core wires unlike Bosch(even at dealer).
MERCEDES BENZ MASTER GUILD TECHNICIAN (6 TIMES)
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
190E 2.3 ITS RACECAR
1986 190E 16V