A box model I made a while ago and forgot about. It is great as a destructible object.

It has 768 trinagles but can be easily reduced to less if the inside faces are deleted. The zip file includes 4096x4096 texture and blend file.

Each side is an instance and so a change to one changes the rest. This also means you might want to just join them all in one object after you make any changes you may want. 

Donations appreciated and they will be used to improve my 3D through new software or extra time spent on the models. They can be done using this paypal link.