couple of months back i installed bosch 4 platinum in my m20. Many told me i made a bad decision and ive read a couple of post that it was not a good plug which now i know its true, had bad idle , bad fuel economy etc... just today i changed it to denso iridium plugs. I ask in shops and they want almost up to $130 for 6 plugs. Went to our local yard and to my surprise they had 6pcs. laying around bnew! and they gave it to me for 1000 pesos or around $23 for 6plugs! was that a good deal or what! hehehe its almost free!