Hi,
I voted blacked out stock vents. I have had both in my assortment of cars and vans over the years, and I have reached the point that I like them so much, I now
think they look better.
When I first got my Rabbit-based Pickup some years back, I could have had the vents replaced with fixed vents from a junk yard for $30 total. I spent over ten times that for hinged-and-riveted replacements from the dealership. (All MkI Golfs without fixed vents seem to need them replaced anyway.)
It was money well spent.
I might add that my Pickup had the sliding glass rear window. I'm adding that caveat because you just added the sunroof. The vents function differently from sunroofs, roll-down windows and pop-out rear windows (should you decide to add those later) whether you use them separately or in any combination.
The only concern I have is they are an inviting source of a parking lot break-in.
Now when is this contest? I can't wait to win your car!
-René