The door seal on the Mini seems to have changed with each model update. The MK3 & later (any car with roll-up windows) door seal is notable because of its large 'bulb' area. The 'bulb' is the round section that the door closes against. The size is determined by how much gap the door leaves. If the bulb is too small, as is found on the MKI and II weatherstrip, then the air rushes in. If the MK3 surreound is used on a MK1/II then the door is VERY difficult to close!