N split - so true.
I guess your best source of information is Robinson themselves. Despite their current size, and growing, you can pick up the phone to their engineering people most days. Being cautious types they will give advice but not direction, and from this you will probably be able to work out if it is economically repairable.
Another source would be an accident appraiser. Even if they are not from the helicopter's insurance company, they may, for a fee come and give an assessment. These engineers are very good at working out what is worth the repair.
My own guess from your description of the accident (sounds like one I am very familiar with) is that it will be un-economical. Even when rebuilt, it will still have the hours left on it that it had at accident. You will not be able to zero time it unless you use a complete factory rebuild kit.
And when you re-build it, whatever its value, it will still be an aircraft with an accident history, which can be difficult to sell on.
FWIW