We used to have a fiamma rack on a T4 tailgate. The rack over the years very slightly distorted the top line of the door, but not so you would really notice unless looking for it. The fiamma will also rub marks in your door over time.
However it is a rack you can leave in place permanently, folded out the way. I uprated the tailgate rams to help lift the rear door with the rack and that worked well.
But one summer when fully loaded (11Kg + 12Kg+ 7Kg + 11Kg = 40+Kg) when I bottomoed out the rear suspension going over a railway corssing, the horizontal arms bent a few degrees and you could see some creasing in the aluminium.
I didnt really trust it after that so gave it to a friend for moving a ocuple of his kids bikes around on his T4 and I fitted a tow hitch and now use an Altera Strada 4bike sliding rack which allows me to lift the tailgate when it’s slid back. Much stronger. But cant be left on the van.