Every single item in your list is very common with exception of the power-steering hose (which isn't uncommon, we had one replaced too). High-pressure line hoses are expensive in any vehicle. The trans is the big item every X5 owner is afraid of, and you've got that out of the way along with a bunch of others. Imo, I would keep it since you're capable of diy and the trans will be fine for many more miles to come. You've pretty much replaced all the common stuff. It should be getting to be reliable now. Fwiw, you don't need to replace the O2 sensors after the cat. They don't do anything other than monitor that the cat is ok.