I twisted Lisle bits on the bolts in the bed of my truck. These HF bits have been great, beat on them with my 900ft/lb IR impact and no problems.
http://www.harborfreight.com/8-pc-12-in-drive-impact-star-bit-socket-set-61336.html
http://www.harborfreight.com/8-pc-12-in-drive-impact-star-bit-socket-set-61336.html