Most of the newer Acura's come with stock HID's. A ballast is needed to supply the constant electrical power for the HID bulb. H4 is the bulb used for 96+ Civics and D2S is a particular HID bulb. HID's are gonna be much brighter than non-HID lights. Advantage of HID s light output, but it comes at an additional cost (for cars without it). HID's are also classified by temperature color: 4100K (slight to no yellow tint, so mostly white), 5000K (bluish tint), 6000K (purplish tint). The 5000k and 6000k offer no more light than the 4100K. IMO, they just look cooler :naughty:...