i doubt the OD of the plennum inlet is even 80mm, you wanna get a caliper onto it and check it out, also you will need different bolts to attach the throttle body.
and because the xf tb's are a lot longer you have to shorten the accelerator cable, dont do what the wankers do, use a long bolt and spacers on the throttle cable bracket, just mount it like normal and pull more cable through down at your pedal, its actually easier and then your motor doesnt look stupid.
just doign over it in my mind 80mm would be covering the bolt holes in the plennum chamber.
check your measurements first before you go modifying things because i have read the hot-to's and guides and i did it all myself without help from any of the guides cos they all had the wrong info or really dodgy ways of doing things. It sounds easy but its actually quite hard to fit the 68mm xf tb onto the rb30 manifold, very tedious. It took me the best part of a day
