It's all the same. HB2, H4, 9003. In fact I've had one of each "size" in my car. I tried the Piaa looking for whiter brighter light, but only got dimmer blue light. Seriously, I went back to the stock bulbs and noticed they made more light. I finally found the holy grail of halogen bulbs. Trust me on this, Sylvania Silver Star's. The 9003 is the one you want. A pair will run you about $40. On the same wattage they burn brighter and give you more light while a very faint tint gives you 4000 degree Kelvin light which is a lot closer to day light. It's the closest thing to HID you can get spending less than $300. Plus, the Silver Star's are DOT approved too.
BTW, if your truely set on Piaa bulbs I'll shoot you a deal on a slightly used set. :wink:
BTW, if your truely set on Piaa bulbs I'll shoot you a deal on a slightly used set. :wink: