Re: Safety?
Depends on the Discovery, the D1 is very similar to the original Range Rover and the 90/110, the D2 was the last new live axled design and I was surprised the axles did not end up on Defenders. (But the engine & manual gerabox did).
D2, D3 are very different, independant suspension, and a transmission unrelated to anything before.
The D1 and D2 are both about 100" WB so are between the 90 and 110 in size.