I've heard a rumour (Dunno true or not) that double core spark plugs ie:-Splitfire,NGK CopperCore plugs can make ur pistons "berlubang"cause of the overspark especially if ur car engine is bone stock standard.Is it true:questionmark:
http://www.blogsmithmedia.com/www.autoblog.com/media/2007/04/kbb.jpg
Here are a list of cheap cars as compiled by the Kelley Blue Book. Though it certainly does not apply in this part of the world...