Just something that i experienced, is that you don't want to have your boost coming down right onto your carb like that, it makes it a bitch to tune because it causes some problems with the petrol in the bowl if i remember correct.
Here's my MK 1 set up:
That's the main reason why i changed to a dual carb set up - meant that i could have the boost entering between them and not being forced directly down the throat. Ideally if using one carb you want a decent "box" on top and have it entering that before.