You may be surprised at how little the difference is between 4.56 and 4.11. I know you can do the math, and come up with precise numbers, but the difference in "feel" and how it starts out in 1st gear will be what counts. If the donor is a 4.11, I would put it in and drive it for 2 weeks to get used to it, see how you like it. Try the short runs to work, and around town. Find a safe spot out of traffic and see if it can be stalled starting out in 1st gear, or what your limitations are!
Personally I went from 4.56 to 4.11, and wish I went to 3.73. but that is a project for another day.
Good luck
Jon
