friend put a valver in his 1.4, swap rear beam, all brakes and running gear, fuel tank and front sub frame ect and wiring loom. main problem was converting from cable clutch to hydraulic.
goes like a dream though now. depends how much money you got for fuel (me owning a 1.4, i would love it quicker but can't afford the fuel), conversion wise similar things would have to be swapped i would imagine, so wouldn't make much difference between the VR and valver.