I have Ferrita's stainless sports cat back in stock for your car. it is the one that will otherwise fit the V70 T5.
http://kalmar-union.com/parts/volvo-...v70_-exhausts/
i am not quite sure why you would want to take out the rear box.
If you are looking to create a more noticeable sound then it is best to take out the centre box of the standard system.
Don.