Your low beams will be 9006 type bulbs. So when purchasing a HID kit look for a "9006" kit. Also, when buying a kit try looking for a kit with slim and digital ballasts they are the most reliable at the moment.
Try looking for a kit at around 120$-150$. Under 120$ I doubt you get good quality products.
Last one a bought was from
http://www.asxhid.com/ two years ago and it is still working perfectly.
Hope that helped.