Rust concerns...

[Notamech]

37 minutes ago, Mr_Groundhog said:

This is the diff outer side I was talking about. Makes me wonder why they choose materials prone to rusting in some parts?

As pointed above. This is thick steel its not going to rust through. Also i think the diff along with the exhaust pipe  rusts faster because of hot and cold cycles. Its because heat helps with the oxidation process and speeds it up. Honestly having been under the car ..i realised unless this is going to be your forever car rust should not be a major concern. You most likely will move on before it rusts to the point where it fails an MOT. Unless you live in an area where roads are salted very often e.g up north. Thats also another thing to watch out for when buying a used car to begin with. I try to avoid cars from up north. You can make an educated guess as to where its spent its life based on its registration, no of owners and location where its being sold.