I'll just chip in here for the record as Iam working over many scanners at the moment - I have had a lot of luck importing across Prismas, Skyras and even Vidas - some tweaking is required (so getting Frank to double check is handy) but you may be surprised at how little you need to change. Unfortunately I don't have Frank's 258 grid file to share but I work with many similar sets of grids.
Beware the max b-value with the different gradient coil strengths though - you may get very little signal on a Skyra at b=4000, 3000 and even 2500.
Andre'