On the Cupra pd 160 Ibiza the end is an 80mm hole connects straight to the maf sensor but u need to make some sort of bracket to secure it very please with my filter I brought it from part box last week very pleased
I got one of these filters and the end was also rubber. it sounded good while it lasted!!! it was on the car a month before the rubber split ! if you can it would defiantly be worth trying to find a way of strengthening it before you fit it. Badger 5 said it would happen, wish I had listened to him now!