I replaced my springs a few years ago, and it was not much of a problem at all to do. Get a piece of nylon braded cord, 1/8" thickness (like a window blind cord) about 6 feet long, loop cord around the spring end that attaches to body post, tie both ends of cord together, and put a piece of foot long pipe thru the cord, then stand back at the rear bumper and pull, using both hands on the pipe, the spring. By standing back at bumper, you get really good body leverage, and can use your entire body to pull, not just your arms. Once you clear the body post, move the spring a little to the left/right of the body post, and then let up on spring slowly to slackness., you can put on the same way, but will have to cut the cord off the spring once in place, because it will get lodged on the post. Let me know how you do.
Bob