The Triktoys amp wasn't encased at all, just a tiny circuit board a litlle bigger than the FX-board. I managed to get it all nicely into my ANH style helmet.
The best place IMO, would be to place it in the "snout" area. But I don't know how much room the MR CE helmet has there...
I read on another forum, someone bought an wireless transmitter for their helmet-mounted mic, which had a receiver connected to the amp. The amp itself had a bigger speaker mounted behind the chestplate, which in turn produces better/higher sound.