As a newbie I'm often easily confused but trying to learn as quick as possible.
I see D2S bulbs packaged with HID conversion kits, and some will include a "harness" to fit a wide range of sizes. My questions are:
-is the harness for wiring only?
-how will the D2S bulb fit into my H11 housing?
-or am I way off base and all bulbs have a universal base, similar to a house hold bulb where they all are the same.

 

D2S is a type of bulb used in headlights that have projector lenses. The harness is part of the wiring, and is used to hook up the HID kit to your car. The D2S bulb will fit into your H11 housing using the rebased socket of the bulb. Each type of bulb has a different base and bulb, which is why you have to get a kit that is applicable to your H11 housing.