Originally Posted by chrisarella
B. swap out the entire read end, including STI rear axles, STI hubs (5x114.5) and new wheels, and Brembo brakes.
I personally didn't upgrade the rear diff to the r180 because I love my wheels and tires (5x100) and have $3k worth of brake upgrades. Going with the r180 would mean having to get new wheels/tires, brakes, hubs, and the whole sha-bing, totally upwards of $4k when all is said and done.
You could have just stuck with '04 STI bits and not have to worry about swapping wheels and tires.
I just don't see how a new differential itself is really going to make that big a difference in the strength of the R160. The fact remains that it's a smaller diff using smaller gears that are more highly stressed than those in the R180.