Our ABS is comparable to other ABS - it will shrink as a function of contraction from cooling.   Generally speaking, ABS shrink about 1 to 2% from when it is extruded until it reaches room temperature.  HIPS will behave similarly to ABS.

Large objects, especially along long straight edges, will pull in.  To minimize the impact of this, you can print in thinner layers, lower the extrusion temperature (while making sure it's still hot enough for adhesion), and use a thinner perimeter/shell thickness.  Improving adhesion to the bed, and allowing the part to cool  more fully while it's still adhered to the bed will also help minimize the warping of your parts.  To counteract splitting at corners, you can chamfer or fillet the corners to avoid 90 degree corners.  This will help distribute the stress over a wider contact area between layers and lower the chances of a split from happening.