I think there's 100s laying in garages across UK - half of them from members of the Forum. Could be a hard sell; might be better to keep it so you can offer it to a future buyer/part exchange.
Im not the best person to ask mate, im sure someone on here could tell you, its yours if you want it, i will check out the postage on it first. Where are you based
Looking at the size and weight of the parcel it's probably going to be around 25-30 quid, I will know for deffo next week, is that sort of price ok?
Use interparcel... ups parcelforce etc wont cost more than £12 for sending that exhaust mate, just maybe ask few quid for effort and packing etc