I've got Bilsteins on the 5.0 and lock nuts were provided for the three locations on top of the shock tower. Stock nuts were flange nuts and you can see there is a lot more contact area to the tower and they might be a tiny bit taller, too (can't remember), ie: more threads. I checked the torque a while back and most of the lock nuts were not to spec. I don't know if they were torqued during the install, but it got me thinking which nut might actually be better. Or with a bit of blue loc-tite???