SoftBank hasn't been shy about its interest in smart cars, and it's taking that fascination to a new level. The company's Vision Fund is investing $2.25 billion in GM's self-driving vehicle unit Cruise. The cash influx will start with $900 million the moment the transaction closes, and will finish with $1.35 billion once the completely driverless Cruise AV car is ready to launch. The move will give the Vision Fund a 19.6 percent stake in Cruise -- not enough to take control, but it could easily prove influential.