Hey, this is a pretty good attempt at the MoUP, although it seems like the side spikes are a bit too small compared to the original, which makes the eyes look kinda weird (nothing against your model, the original has the eye problem as well, which is why I altered them a bit in my version to make them align properly). Also, I believe some people have already tried replicating 100% TLG's clip-on system, but it always ended up breaking since Shapeways' plastic is nowhere near as durable as ABS. That'd the main reason why other modelers (including myself) have tried to come up with different systems. Mine has been tested and proven to work, so I'll probably share it with the community after I've perfected it a bit.
All in all not bad, do message me if your system works, since I'd be really interested to see how you pulled it off withiut having it break like the previous attempts at copying TLG's system.