Not sure if I didn't post it already but uh..
Unity has some problems with physics. Simulation will give different results in the same situation on the same machine(sometimes) not to mention different computers. Better of reading this unity forum thread.
Im just wondering how its gonna be solved, rewriting whole physics? simulating only on one machine and sending it to another players? The respar like script wont work anymore that way :/ I'm just wondering but if you want to keep it as a secret I get it.