This version uses less space and fewer blocks at the cost of more indivual block connections. While I would consider that an improvement in general Starmade seems to handle it poorly while it functionally does the same thing so it may be worth using the version one of this multiplexer/demultiplexer if running on a weaker machine or until Starmade manages to optimize it's logical circuits. (One day maybe). I hope this proves useful to someone. Thanks for your time.
Volume: 288 blocks^3
AND Blocks: 257
NOT Blocks: 9
OR Blocks: 1
Total logic block count: 277 blocks