I have a 1.9D S S40. It came with half leather seats, but already had the sport trims.
I would leave the suspension as it is if I was you. Brakes are the same in all models.
What colour is your car by the way?
Here is a list of things I've done to our 1.9D:
http://www.volvoforums.org.uk/showpo...6&postcount=10