Can you swap most S line Volvo parts such as the S80, S60, and S40? Specifically things like the exhaust! I would like to get a new axle back exhaust for my S40 t5 and wasn't sure if I could also look under S80 and S60 exhausts as well!

 

Pretty sure that nothing in the exhaust system from an S60-80 is going to fit. There should be commonality with the S40 on most parts, though exhaust might be different (since the back of the car is different). The way I check on things like this is to use the (excellent) Rockauto parts interface, and see if (for example) the S40 and V50 use the same part numbers for the (for example) muffler.

 

what I have done is use a dealer web store to find the volvo factory part number then search on that in Google, Amazon and other web parts stores etc. You should be able to see a compatible model list.