The problem that you are going to have is blinding oncoming drivers. Those kits should be used in projector type enclosures. Your C5 on has projector type enclosures for the fog lights, not the headlights. Adjusting your headlights is another horror story because your headlight adjusting rods are probably seized up by now and require complete disassembly in order to free them. That's a completely different thread.
The smart move would be to go with LED or halogen projector lenses. A LOT more expensive but completely LEGAL and adjustable. It is also much more considerate of the drivers driving TOWARD you. I have Hella projectors but there are others out there to chose from. Plus, I can run all four lights at the same time.