So all the bits that make it go faster than it should then?
This is entirely my point and it's a general one not aimed specifically at you - if someone had said "I want to put 13:1 gears and a mosfet in my Specna Edge so I can make it go BRRRTTT is this a good idea" then we could have all said "no" or "well you can but don't be surprised if it breaks" and saved a great deal of cost and heartache. It's the same as the endless "just bought this is it any good?" posts.
Like I say though, best of luck. My personal advice would be get it going with the replacement box you got on here and the standard gears and keep it as a backup gun. Then go buy a better one to fuck about with.