Jason Torchinsky realized that although it would be difficult to steal the space shuttle Endeavour from Los Angeles, it was not, technically speaking impossible. The heist will just require some creative thinking, a bit of luck and some money. Read his step-by-step plan at the link.
However why would anyone try to steal the endeavour? (especcially if you already have a Buran.... ) It seems easier to get an Energiia than to plot the heist...
If you already have to build a Sub with sufficient cargo hold,it would be cheaper offer the Buran (and the cash for the Sub) to the California Science Center...