hid ballasts
I found it hard to find space for them as well. For the drivers side I took advantage of a flat spot on the side of my CAI heat shield (the box that helps prevent hot air from getting pulled in through the filter). For the passenger side, behind the headlight/in front of the washer fluid reservoir I found a flat area where it fit just fine. To mount them I just used velcro tape to hold them in place just so that I didn't have to bother with drilling. The velcro tape works great and makes it easy to access them if I ever need to.

