I personally stay away from sound decoders, I'm afraid it is too much like drugs-LOL. I think the loksound decoders are small enough to fit. You will probably need to either machine a bigger hole in the fuel tank and modify the motor mount to allow the sound system to fit in the tank, or mount it in the cab. If the Loksound decoder is small enough, you might be able to mount it vertically in the front of the cab, and mock up a control stand and firewall to hide it. The Tsunami may also be small enough to fit. I haven't seen either one, but I understand that both are extremely small.