Exhaust back box replacement

[Loudman]

Last week someone kindly reversed into the back of my car (s2 111s) in a carpark, I wasn't there. They obviously either thought they hadn't done any damage or just scarpered but have in fact broken the welded support to my exhaust meaning that it is unsupported and now rattles. I could try a repair but may just replace.
Question: how much of the 'improved' sound of an exhaust ( larini, 2 bular et al) comes from just the back box or do I need a full change for it to be worth it? ( in which case I probably won't bother)

[noodleman]

Most of the sound comes from the silencer.

Do it.

[nsm3]

Back box only is the major contributor to the change in "sound" - not sure about volume but I suppose taking the CAT out would have a big impact on that?