The Tough box is nice. It used to be included in the kit, but this year they switched to the less expensive CIMple box. However, it is heavy and you probably don't want to waste the weight on four of them (not that it hasn't been done).
I have no experience with the P80, but I do know that cantilevered outputs lead to bad stuff with them.
If you don't really need 4 separate gearboxes, I would recommend 2 tough boxes with 2 CIMs each. Otherwise, the P80s would probably be lighter. You can also get the P80 directly from banebots,
http://banebots.com/pc/P80K-S4/P80K-44-0005 , The price winds up being the same if you get the same options offered at in the one sold through robot shop, but the shipping might be less. Also, If you do switch to 2 gear boxes, the P80 has a 2 CIM option as well.