I purchase a lowering bolt kit for my 07 C6.
Install them, great directions, great price $50.00
7 months later and 10k miles plus a weekend of track time doing hot laps. The rubber on the bolts split on both sides of the rear wheels, this made the metal tab of the bolt rub against the aluminum A arm creating a really bad sound.



I fix the problem by making my own using some hard Teflon stock and machine the pieces and install with ribets to the bolt tab. No sounds, no need for grease.
This material is a low friction and will not collapse under pressure.

Be ware of cheap lowering bolts, well....that is all that is available, to bad