I've parted out my Specialized Crux (aforementioned in another thread) and in doing so got to weigh the individual components. A few things came up:
First, the fork... weighs in at 567g with crown race and this spacer thing below the race. Unfortunately I don't have a crown race remover, nor a remover for that spacer thing, so I have no idea what that spacer itself weighs. Anyone have insights into this?

My first thought was WTF is this?!

Then I took a look at the headtube:

Apparently there's some extra distance between where the crown race would meet the lower headset bearing and the bottom of the headtube, hence the extra spacer. It also looks like I have some optional space to dremel out excess tubing and lose 10g or so, but that's another note.
Which brings me to the fork replacement I'm considering:
This one... simply by way of budget (because an ENVE fork is out of my budget at this time) -
Sette Tapered Fork - claimed weight is 500g.

I'll also need to add in a spacer apparently, similar to the one that is on the existing Crux fork.
Could this spacer be made of carbon fiber? I could have one made.
Is it worth the investment to get a full CF fork? Or should I just stick with the existing fork with alloy steerer?
Are there any other options out there that would work with this Specialized headtube design? (see what I did there?) I'm even wondering if the Sette fork would work considering how far up the 1/2" size rises from the crown.
Intentions of the build will be:
60% training/trail riding in the local mountains, heavy thrashing anticipated, lots of climbing on hard packed dirt (Southern California)
30% thrashing around at a few races during the season
10% idle cruising on backroads