I am half and half on this. In comparing to items sold in Japan its hard to not want to bring up the fact that you'd also be charged for Sal or EMS shipping rates, and that EMS can be expensive, but also work in your favor if you order a lot of games included with the item from the same seller. Here in the USA, I have been able to send 40lbs computers in 22x22x18 size boxes full of extra packing material to either Ny or California for about $36.00 to $39 insured. Obviously the bulk of that cost is due to the sheer weight of the item, so something like a Duo system wouldn't even begin to compare in shipping cost. It would be best to just pre-pack it, weight it, and send a exact quote amount to save from any confusion.
All that being said, I would be hard pressed to either endorse, or scrutinize, Deans work quality on the region mod, but am opting to mention that on a Coregrafx purchased from him the mod work came undone some during shipping and I had to repair it, and also had to repair a Supergun that he built that was sent to me to work on. If nothing else I would just state that due to that I would take extra precautions in regards to packing material to ensure that the item arrive safe and sound.
To me, from a users standpoint, the box being included does not equal a cost difference of buying a RGB modded system that probably had a new laser installed also. From a collectors standpoint that is probably going to differ some. To me I would say $180 shipped would be a reasonably decent asking price for a boxed unmodded deck.