The KWA's body is fiber reinforced ABS as apposed to the SRC which is nylon fiber mixed with glass fiber. Which is what the real gun is made out of, if what 007 states is true SRC have better externals. Plus you got the metal charging handle and mag release, and personally I think SRC look better
. When it comes to Internals I don't know enough about gearboxes to tell you who is better.
Ian