Okay, ive read the threads and I am confused . What ballast does the 2006 STi use ? Can I order a aftermarket one got the bulb just need the Ballast, I need to do this the most cost effective way, its christmas time and I am broke .

Thanks John

you dont want an aftermarket one, get an OEM one

ebay. get OEM the nissan one is the same as ours.
http://cgi.ebay.com/ebaymotors/Infiniti-Nissan-OEM-Xenon-HID-Ballast-G35-350Z-D2S-D2R_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c66Q3a2 Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3 a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem 320321476642QQitemZ320321476642QQptZMotorsQ5fCarQ5 fTruckQ5fPartsQ5fAccessories#ht_681wt_0
like that