If your aiming to build one of these 
you should leave it at 
and its preform and just start building your next item. You can only have 3 wards out so the bonus ward doesn't change much and the stat increase isn't really worth the gold. Supports don't tend to run into the issue of not having enough inventory space early to mid game so skipping the final form for later to start another item is way better.
The More You Know
meowwow71 votesor yet 
with a 
although the would be best for it
Oakleaf Ranger2 votesI'm not a fan of those since I prefer slot efficiency. It is why I said if your aiming for one those combination items though since the main reason in the first place for me is to allow more items.
meowwow71 voteswell if you are using a ton of active items as a tanky support it comes in handy
Oakleaf Ranger1 votesno I need room for this 
MysterQ1 votesI used to think that way. But I have heard from many higher level players to rush my combined sightstone. I will only do it if I have a spare 550 and no components to buy. But just saying others have said to rush it.