First you'll need to start with the Mi-Go Racial Template which I've got in .html, .gcs, or on
Myth-Weavers. On top of that feel free to spend 20pts with up to 15pts with of disadvantages. I encourage some of those points be spent buying off existing racial disadvantages, and remember that generally speaking it's a good idea to have a lot of different skills in GURPS. Off the top of my head the following might be Mi-Go appropriate, but I can speak on how effective they will be: Lightning Calculator, Diagnosis, Buy off your flight limitation, Sadism, Additional DR, Trained By A Master (If you
really want to unleash the Mi-Go kung fu), Magery 1 (specially FTL Comms, Changing Form, etc).
You've all been surgically modified to be able to speak with sound. You could not have it and trade Disturbing Voice for Cannot Speak for a net 15 points.
In addition you may also start with your choice of a Mist Projector or Lightning Gun, and everyone gets a dose of 50lb strength removable adhesive!