Re: 3/4 ellipical suspension
I don't have direct experience with doing this type of mod, but a 3/4 elliptic to my knowledge is basically a 'buggy leaf', where you take a main leaf from another spring pack, cut it down, and bolt it to the frame and have the shackle kind of hanging suspended between this buggy leaf and your main leaf. This allows more droop.
Generally speaking I think this setup is inherently less stable than stock, with a lot more side movement of the springs, and therefore I think generally not recommended for a daily driver.
That's what I've HEARD. I'm sure there are others with more direct experience.