Well it depends on the year of your X.

But the baffle (waffle looking thing) in front of your lowbeam will have a hole in the center of it.

On Halogen headlights the baffle is solid.

__________________
2002 4.6is Dinan S2
Titanium Silver/Black Alcantara

DINAN
Stage 4 Engine Software
Automatic Transmission Software
High FlowThrottle Body
Free Flow Exhaust
Cold Air Intake System
High Flow Air Mass Meter
OTHER
CCFL Angel Eyes
Stealth XM Radio in ashtray : FM Mod
Pilot H3 Fog Bulbs
Cleared Headlights: Hi/Lo Beams
Hardwired Radar Detector
IN PROGRESS
Powerstop C/D Rotors: (on backorder)
W/EBC Red Stuff (F)
W/Axxis Deluxe (R)
Dice Ipod: Aux Input for XM
THINKING
SMG II
MK4
Bluetooth