Try to find an 80-85 toyota pickup for a donor. The toyota axles will be best. You DO NOT have an offset rear in the Sidekick. The toyota axles generally have a 4.10-4.88 ration, with the vast majority being 4.10s, so plan on gears, they have 5.29s and like 5.78 or something ridiculous like that, the 5.29s are pretty reliable, the 5.78s are the highest available and consequently the thinnest ring gear. Leafs front and rear is going to be the cheapest and easiest to fab. Either Toyota rears or YJs are the most realistic. Sky's has spring and shackle hangers for toyotas pretty cheap. Sidekick frame is close to toyota, but not exact. BRACE THE FRAME!! The track/kick frame has "crumple zones behind the struts on the front. They bend easily, they are meant to. Mine bent before I realized they were there. If you get a donor rig, you can chop some of the spring hangers and stuff off it, plus you can sell of the crap you don't want to help fund the build.