Do I Need to Replace the Rear Diffuser on My 2005 Z4 with High Mileage?

I'm considering replacing the rear diffuser on my high mileage 2005 Z4 with some trim and aesthetic upgrades planned. However, I've never done a job like this before and want to know if it's even necessary or if there are any specific concerns I should be aware of given the age and mileage of my vehicle.