Unless you need new wires, a tune up for your car should be plugs only.

Your model, fortunately, does not have caps and rotors (I'm pretty sure). If it did - you'd really be in need of a tune-up by now.

You can do plug wires if you want, but unless the resistance is out of spec, it may not improve anything.

Best of Luck,

Troy
1995 E420 83k