I've got these in my Ph1 172.
HID kit: http://www.ebay.co.uk/itm/200962964560
I found the bulbs a bit too blue so bought a whiter bulb replacement as I couldn't find a cheap 5000k kit. These are the replacement bulbs:
http://www.ebay.co.uk/itm/330776186460
I also got some Cree sidelight and full beam bulbs:
http://www.ebay.co.uk/itm/140825715721
http://www.ebay.co.uk/itm/121264301186
Guys, what are the bulbs like to change on a 172 Cup? My NSF dipped beam has gone so need to replace, can get Ring Ultimate Xenon or whatever they're called cheap off a mate so going with those, probably do both dip & main beam while I'm at it but want to know how easy/hard a job it is?