There is a special tool for removing & installing those bushings that costs just under $100; might not hurt to check around to see if anyone has one for rent or for sale. I've had some success using plumbing fittings for other bushings, but considering the time it takes to gather parts & cobble things together, I've become a fan of spending the money on the right tools for the job.

If the diff is like others, it pretty much just bolts up, and there isn't much adjustment room, so alignment isn't an issue. Getting it lined up though can be a bear. You'll definitely want to have some kind of jack to lift it into place; these things are heavy. The e32 medium-size diff I sold & shipped last year weighed 90 lbs with the crate. I installed a similar diff on my 735i last year & just used a standard floor jack but had my son under the car with me to keep it steady and get it lined up. If you're doing the job solo, a transmission jack would almost be a necessity.

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2001 X5 Sport 3.0/5-speed
1998 318ti/5-speed
1988 735i/5-speed
1984 528e/5-speed (soon to be M20B25-powered 525i!)