I can give you a good threat... move it safely or else.

If I understand you right you are upgrading from an eight gallon to a new 30 gallon and can you use your old materiel into your new tank.

I moved a hundred gallon into a 190 gallon. You have to think about disturbing the sand bed in your old tank (depending on how long and how deep you have it) for fear of releasing a lot of crud into the water. But your building up from eight gallons to thirty and I imagine that you don't have much sand in the biocube. You should be good. And using your old water is okay, especially since you will be adding about twenty more gallons.

There are more things that will play a part in the final way you hook things up. Will you be bringing in more sand? More live rock? How long has the biocube been running? Willl you have a sump/fuge? If now, have you considered using the bio cube as a sump/fuge?

As far as moving the tank, shouldn't have any problems. When it's in your car/truck just ensure that it sits flat.