Hi Painless,
I have fitted one of these systems in two shermans and found the best way to mount the MFU with the fan on is to pop off the bottom plastic cover and replace it with insulation tape. It will then fit in the same gap that the old rx18 did between the battery box and hull side.
This is actually a ploy that Taigen use to fit one of these into their Pzr IV where space is very limited for the MFU. They come from the factory with no bottom plate on the MFU and with the bottom of it hot glued directly to the hull.
Another way would be to leave the bottom plate intact and remove the fan. The fan looks great but I have run these units with no fan with no problem what so ever. They don't seem to overheat anyway. I wonder if it is perhaps a bit of a sales gimmick or only necessary for the very heavy tanks which will draw more current when moving. It is all extra draw on battery power whether it is serving a purpose or not
I suspect other solutions may require removing the battery box and having some sort of quick release system for the upper hull to remove the battery. I have moved on now to other control systems but this still seems the best option for MFU mounting.
With the switches I swapped the main switch for a mini toggle switch which is positioned in the rear hull plate above the left track. When the top hull is in place the switch cannot be seen at all, but is still relatively easy to operate. The smoker switch I don't need now as I am using the IBU2 board which has the smoker controlled from the TX. The speaker pot I upgraded to a better quality one with a metal base and hot glued it direct to the hull.
Hope there might be something you can use there
