General rule is you will never make money out of 'projects' let alone incomplete ones, of which I take it you are at terms with.
From my POV, it's not worth any more than a stock (legal) 318ti, as someone (who knows what they are buying will also be buying the risk(s) associated with getting it legal, and thus will be looking for a 'bargin'. Harsh I know.
The flip-side it there is always someone out there that doesn't know sh!t and may be willing to pay the value you are looking and not care about the legal side of things.
It sucks you're in this position of getting rid of it, as it would be much better for you to get it cert'd and enjoy it for a while, thats why we do these projects isn't it....