The beauty of the Vertical In-lines is that the top-like motion of the motor causes very little vibration. Imagine it as an upside down pendulum with the fixed point being the pump casing. Even if the motor may be vibrating at 1.5 mil, the effect at the piping is theoretically zero and is actually very little. The minor displacement is easily taken up by the piping spring hangers.
Pipe mounting is the preferred method for VIL installation.This eliminates the concrete, springs, and required floor space.
"But we live in California!" you scream! Never fear. Those designing in Earthquake Land simply provide pipe supports on neoprene pads for seismic projects. Which is still lower in overall cost than concrete inertia bases and spring isolators.