My 2010 C300 has cheap after-market HIDs, which I would like to change back to halogens. Is that a simple plug-and-play process, or is it more tricky than that? Thank you.

It should be plug and play once you remove all that after market stuff. Did the car come with the original headlights as well?

Thanks Colin. The car did not come with the halogen bulbs, just the HIDs. Are there any that I should or should not buy?

Oh, you just have HID bulbs fitted and not aftermarket HID headlight assemblies?

Just pop the H7 bulbs back in.