I just (last week) bought a set of plugs, the HR6DS, as recommended. The price was $6.00 / ea. the cost of the platinum HR6DP, was ~$3.00. I did question the cost difference at the time & decided to go with the recommended plug. Was this a bad move???? I'll tell you in another 50K miles ------------------------------------------------------------------------ To address comments privately to the moderating team, please address moderator@xxxx