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