Motability astra exhaust alloys mods?

i have an astra sport hatch on motability and am wanting to add a louder exhaust and better alloys, i am aware the car must go back in the exact same condition as it was when i got it but are exhausts easily fitted so they can be detatched when the car has to go back. i have been looking at exhausts specifically to be fitted to astras so will i have to remove anything from the car or are is it easy.