Instead of a whole cradle swap, just do the 09 axles, driveshaft or any one piece for that matter, and diff. If you can shove a Dana 60, 9" ford or 8.8" cobra diff in there than a V2 diff could be made to fit. Add the different size half shafts and you have helped to reduce the wheel hop and have a diff that can take the abuse if it did. Its already been said for a V2 cradle swap fabrication needs to be done so there will never be a bolt in solution. This way you dont need to buy the gas tank, rear cradle, and all that jazz. All you would need is the diff, a couple axles, and a drive shaft and a good fab shop. Everything you would need for the whole cradle swap but this leaves fewer parts to be purchased and maybe a tad bit more fabrication.
Here is another question. If you do swap tanks, will the existing sending unit be compatible with the new tank? Will we have to use the V2 sending unit and will it be compatible with the our car? Is the fuel filler in the same location? Are the straps in the same location? Are the fuel lines the same size? All this stuff would have to be figured out to do the V2 cradle swap. I say just modify the V1 cradle to accept the V2 diff and call it a day.