Hello,
Servonaut runs with 7.2 or 12 Volt. You can switch.
Visit the servonaut - homepage to get more information about.
http://www.servonaut.de/shop/index.php?language=en
How it works with MFU - I don't know. I think you will find some more information in german foren as
www.modelltruck.net or
www.modelltruckforum.de. But those discussions are only in german language.
Maybe it helps.
Regards from Lübeck / Germany