It's hard to say without knowing exactly what's involved in that 5k quote. It's not as simple a job to "finish" a 4700 series roller as some people may think. Even if you have a finished motor and trans, you still need to setup the bellhousing. Most people use the Lakewood setup, and that can take a few hours alone to setup the clearancing. I've heard there are starter clearance issues, clutch linkage issues, motor mounts issues, etc with the 4700 cars. Then you have to plumb all the
oil cooler lines and finish off the engine bay. Once that's done, it's onto the exhaust. The headers and sidepipe come with the 4700 cars unassembled, which means you have to build the headers and hang the sidepipes yourself. That alone can be $1000 of labor. Once all the mechanical stuff is done, the car has to be fired up, checked over, tuned, road tested, then rechecked. Then after 500 miles or so, the car needs to be brought back and rechecked again.
So 5k could be a good price quote if it involves most of the above.
BTW, have you taken delivery of 4769?