I guess you just mean the globes? or the entire assembly?
If it is just the globes than it is really simple. Just pop your bonnet and reach behind the headlight, feel for a round palm sized casing on the back of the headlight; simply twist that right off. Now there will be two wires attached to the back of the globe, just pull that straight off than unclip the wire that holds the globe in place (squeeze the top two tags). Replace with a new globe (do not touch the glass!) reclip and place the wires back on! The left side is a little trickier because the air intake is in the way. You will need a 10m spanner socket to take the two bolts out than pull it straight off the air filter intake; and repeat as you did for the right side!
easy!
With a hammer
The 2006 Subaru Impreza has 16 valves.
The 2006 Subaru Impreza has a 5-speed manual.
The 2006 Subaru Impreza is a gas-powered vehicle.
The 2006 Subaru Impreza has a flat 4 engine.
The 2006 Subaru Impreza has single overhead cam (SOHC).
The 2006 Subaru Impreza's turning circle is 35.4 ft..
The height of the 2006 Subaru Impreza is 4 ft. 10.5 in. (58.5 in.).
The 2006 Subaru Impreza is 14 ft. 7.4 in. (175.4 in.) long.
The 2006 Subaru Impreza has a drag coefficient of 0.34 Cd.
The curb weight of the 2006 Subaru Impreza is 3071 lbs..
The 2006 Subaru Impreza runs on regular unleaded.