H3 were to be for spotlights which I posted about on another thread, but it was suggested that 2x55w halogen spots may be a bit too much for the C5, so I was enquiring as to H3 LEDs and the possibility of H4 LED and use perhaps H3 Halogen........confused? .......I am!
an H4 LED will lower the demand, but, it won't be enough to account for the increase that a pair of 55watt H3's will add.
there are a variety of H3 style LED implementations available, some are totally worthless, and, others have varying sizes depending on the number of LED segments in their design.
If you can define your maximum size parameters I think a trip around eBay will be "enlightening"......