It all depends on how hard they're worked - fully on competition rally driving would kill them in less than 5000km. That's why those guys use fully rebuildable dampers (with adjustment to allow for the wear before they get totally stuffed).
Personally:
Ordered my front spring distance kit.
Did a genuine sub 4l / 100km along Beach Rd from Moorabbin => Port Melbourne with medium traffic - stick that up ya hybrid a$$, Prius
Bookmarks