Z840 GPU and Warranty Questions

Hello,

The business that I work for is looking for workstations and the Z840 has our interest, but we have a couple questions. The workstations will be used for engineering  purposes (AutoCAD, RISA, etc.)

1. What are the capabilities of the integrated graphics card?
2. Would adding additional RAM or a GPU after the  purchase of the workstation void the warranty?
3. Would the power stock power supply be able to handle a GPU if added?

Thank you

Rob