HID bulb replacement is a straight forward DYI procedure that will take you less than 30min out on the driveway. HID bulbs are D4S and are the outside/more lateral bulbs.The bulb itself that you are replacing actually points towards the lateral side of the car, NOT towards the front like you might think. When looking at your headlights from the front of your car, they are the "X" bulbs in this illustration:
passenger side X O O X driver's side ( "O"s represent your hi/low bulbs which are NOT D4S)
On the passenger side, remove the LEFT lateral plastic engine cover after popping out the retainer clips by pushing down on the centre and then lifting on the outer rim with a flat blade screw driver. There is one 12mm black plastic nut that you'll need to unscrew using a 10" extension and socket(don't worrry, the nut is attached to the engine cover so it can't be lost/dropped). Locate the black rectangular cover for the bulb; it faces sideways/left and has a yellow sticker on it. Flip the wire retainer towards you and remove the cover/disconnect the silver metal electrical connector by turning it counter clockwise approx 1/8 turn/release the bulb retainer wire loop ends by pushing lateral-and-down on the top loop and lateral-and-up on the bottom loop/the bulb will partially "fall out"/put your new bulb in(rotate gently to seat it properly, the two tabs on the base of the bulb can only fit one way into the bulb receptacle slots)/secure the bulb by putting the wire loop ends back/re-attach the silver metal electric connector with a 1/8 clockwise turn/replace the black plastic rectangular cover that has the yellow sticker/secure the wire retainer/replace the engine cover using the clips(OEM replacement clips are available on eBay http://www.ebay.com/itm/400736632195?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT and cost less than ten cents each) and gently tighten the 12mm nut.

On the driver's side, the procedure is a mirror image of what you did on the passenger side with one addition: push the windshield fluid white plastic filler hose out of the way after removing the 10mm black bolt next to the fill cap(don't forget to re-position and secure the filler hose before you put the driver's side engine cover back).