Ha ha ha - You gotta love the "service managers"... they know it all!! - LOL
I've been running an aftermarket HID kit (w/ no error message) in the stock SE headlights without any issues - 55W AC Ballasts and 55W 4300K H11 bulbs.
I also just recently added a similar set but 35W in my fog lights... no issues there either. If the ST3 Headlight Housing is physically the same, you'll just need to wire or retrofit the D1S bulbs into a ballast and you should be good to go. Assuming the auto-leveler doesn't cause additional issues.
2012 Candy Red SE Manual... I smell serious trouble.