The best replacement for spark plugs is platinum.

The best alternatives to spark plugs are rated as following:
★★★★★  platinum
★★★  copper
★★★  cold spark plugs
★★★  platinum spark plugs
★★★  ngk
★★★  fuel pump
★★  regular spark plugs
★★  coil pack
★★  glow plugs
★★  non resistor
★★  bosch
★  transmission
★  champion
★  bosch spark plugs
★  fuel filter
★  iridium
★  wires
★  ignition coils
  double platinum
  iridium spark plugs
  alternator
  hot spark plugs
  bad spark plugs
  9.2 spark plugs
  denso iridium spark plugs

Your alternative for spark plugs is not listed? Suggest!
Speaking about spark plugs, one probably shouldn't forget about oil.

Other search terms related to spark plugs and their ratings are:
★★★★★ oil
anti seize
iridium
You have in mind a companion for spark plugs and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of spark plugs in all years. Click on graph for more.
spark plugs
platinum
copper