HEy I know what are u talking about, the sylvania silverstars are the bluish bulbs u can install them direclty in ur stock headlights, but they are not HID they just give u a little bit more whitish look than ur stock yeallow bulbs, i had them on my audi a4 before and i think they are a waste of money, but they sure do look a litlle bit more whiter than the stock halogen bulbs no difference in lighting whatsoever. Well if u want real HID lighting you have to get the HID conversion kit, here is a areputbale seller,
www.kaixenkits.com.
So if u have any more questions, feel free to ask...
Preyash
Here is info about bulb sizes with numbers, hope it helps...
Low beam headlamp
9006
9006ST Silverstar High Performance Lighting: The Whiter and Brighter Halogen
9006XV XtraVision Halogen Upgrade: Up to 20% Brighter
9006CB Cool Blue Halogen Upgrade: White Hot; Super Cool; 100% Street Legal
9006LL Long Life Halogen Upgrade: Lasts one and a half times longer
High beam headlamp
9005
9005ST Silverstar High Performance Lighting: The Whiter and Brighter Halogen
9005CB Cool Blue Halogen Upgrade: White Hot; Super Cool; 100% Street Legal
Parking light
7528
Front turn signal
7528
Rear turn signal
7506
7506LL Long Life Upgrade: Up to twice the life of the standard lamp
Tail light
5007
7528
Stop light
7506
7506LL Long Life Upgrade: Up to twice the life of the standard lamp
7528
High mount stop light
7506
7506LL Long Life Upgrade: Up to twice the life of the standard lamp
Fog/Driving light
H1-55W
H1ST Silverstar High Performance Lighting: The Whiter and Brighter Halogen
H1XV XtraVision Halogen Upgrade: Up to 20% Brighter
License plate
6418
Back up light
7506
7506LL Long Life Upgrade: Up to twice the life of the standard lamp
Front sidemarker
2825
Glove box
6418
Map light
6411
Dome light
6411
6418
Trunk/Cargo area
6411
6418
Under hood light
6411
Instrument-general
2721