According to threads on here documenting these very swaps that is not true. The A500 WILL need a fairly extensive mod to the crossmember, but the floor does not need to be split open and expanded.
The 518 needs much more work. There are at least two good pictorial threads on here by members.
What I'm saying is, "according to." If someone has actually DONE this with a 518 and not had to hack up the floor I'd sure like to see it.
