Replacing a headlight assembly is basically a bolt off, bolt on operation. Upgrading to HIDs is typically plug and play but there can be the occasional modification needed.
That said, if you are halfway decent with a project and have a few basic tools, you can replace your headlights.
I'm trying to find any previous DIY here for replacing headlights but I can't find any right now. Fwiw I've ordered a set of the CGs so I'll be doing this very soon. Worst case, I'll create a DIY as I go.
This of course is all for a pre-2008 model...