Since we base all of our COTMs around Xmods we like to see as much Xmod based RCs as possible. A MiniZ with an Xmod motor obviously doesn't make the cut, but if you have done something along the lines of what RedSXmodder did with his RCP Ripper project that would be acceptable.
Naturally it is rather difficult to judge "what is" and "what is not," but if a majority (50%+) of your entry is Xmod based with Xmod parts it will be eligible.
Cheers,
Kyle.