For the ultimate in stealth mode, upgrade your robot with laser eyes. Now, it's like having a built-in thermal imaging camera.
For the robot that likes to get its hands dirty, upgrade your robot with oil slick treads. Now, it's like having a built-in traction device for those slippery floors.
For the robot that wants to light up the dance floor, upgrade your robot with a disco ball. Now, it's like having a built-in mirror ball.