Yeh it's much harder with the Cupra intake pipe, all other models have a smaller intake pipe and it bends a lot easier and there's a lot more room....
Like i say, i think just give it a damn good jug. It's like a V shaped rubber that goes over a peg in the engine bay. When replacing the air box it goes with a bit of thud. If I were you i'd just give it a decent yank! just don't blame me if anything does break!
Might be better to ask a Cupra owner, just incase they're different for some reason!