You are calling them spark plug wires, but they are technically coil wires.
I wouldn't recommend replacing them, but you can if it makes you feel better.
Remember, it's not the coil wire that goes bad, but the connection with the resistor end.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".