I just stumbled on this. Whatever the cost of parts are at any autoparts store, double it or triple it first off when it comes to a dealer. Then there's the dealer labor rate: I've seen the average set at around $110 hour? Some are more, few are less. Also, whats involved in said "tune up" ??? You've got me curious now. Theres nothing for them to tune, so do you mean them just installing plugs? More info please