Eberspacher cats (factory) are shipped from germany for one, costs more to make them over there, they are huge, and have a flex pipe build into each of them.
To remove them on a manual its not that bad, you have to take out the engine wiring harness and air box to get to the top bolts, then just loosen the rear of the subframe to get the rest of the bolts and weasel them out.
On the automatic on the other hand, you have to break out the engine support tool and hang the engine down 1-2 feet just to get enough clearance to get them past the transmission, 6 hours is less than it should be actually.

 

damn... sounds fun to do.... could I just knock out the **** in the cat haha or wouldn't that work too good?