The Firelap 4.0 body works with the iwaver/kyosho/gpm alloy damper mounts.
The RX board on either does not have brake. It is TX controlled breaking. You would have to use the Firelap TX to get brakes (kyosho TX with firelap RX would go straight into reverse I think)
The steering on the kyosho is a little nicer. People have said the kyosho plastic is a little better too, but if you are upgrading to alloy, it’s less of a concern.
-JNY
