Found this really great fic I've always wanted to read.
"A Soul in Epilepsy”
By: Alida Hush
Pairing: Spike/Xander
Summary: Post-Him, AU after that. Basically a replacement of "The Killer in Me" without the bits in between.
http://forum.buffyworld.com/showthread.php?t=27196 It's great, Xander dealing with Spike when the chip starts to zap him.