Really? Not even the MERFs?
From the Evike description "No modification to your AEG is required just plug and play, but will not stop Trigger contact Arcing."
The idea behind using mosfets in airsoft is to send a very low amount of amps through your contacts. When the contacts complete the circuit (you pull the trigger), the mosfet get's switched on and sends either as many amps your battery can provide, if you're limited by your battery, or as many amps your motor pulls, to the motor which bypasses the contacts. Those inline mosfets that don't require any soldering don't separate the contacts from the motor.
So while they don't save your contacts, they do add other features which I'm sure you're aware of.