I just purchased an *established* tank and a day after the move all of the fish were dead. If I were to do it again, I'd move the livestock to an established location and spend a few days testing to ensure everything will be ok. I'm no expert but it doesn't feel good when you flush $500 down the toilet.
All of the water to be kept was pulled out before disturbance and new sand / stability was used
. The tank is now in a wicked cycle.