The benefits of belvederes are only evident when driving in a way to feel them, 99.9% of the time I'm just nipping up and down a carriageway with cruise control set at 55-65mph or into town. I won't feel the benefits of the belvederes in that driving style, and the lightweight benefits of them are there to counteract the poorer fuel usage associated with winter tyres.
Also i think 18's are too small on the mk7, so the Brescias are purely an aesthetic choice.