I've read up on it a little, but am not clear on what will bolt in. I'm looking to get a lower ratio (numerically higher) in the rear. Lots of 3rd members for a couple hundred bucks with lower ratios, but most seem to be from 535's.

What needs to be changed to use a big six differential in my car, or is it even possible? Axle flanges?

If I can do it for $200-300 great, but I'm not interested in actually swapping gears in my dif.