Demon exhaust on a 4 doors Dart?

Hi,

I happen to have found a guy who is selling complete exhaust (2.25" with Dynomax muffler) out of a Demon with a 340. 300$ for the whole thing (apporx. 10 000km on the exhaust), is it worthed?

I was wondering if it would fit on my Dart with a 318?
From my Service Manual the Demon as a 3" shorter wheelbase, so I guess I would have to extend the pipes by 3", but other then that will the manifold flange fit? Are they at the same position according to the frame/steering component?

thanks