Dealer cost for a Mk17/19 kit is almost double their cost for a Mk25 kit. It's the diaphragms (plural) in addition to the usual seat and Orings.
$50-60 retail for a Mk17 kit is average.
$35 for Mk25 for comparison
$50-60 retail for a Mk17 kit is average.
$35 for Mk25 for comparison