If I built it every time I hit the button to fire it, every second I'd think "supercharger, rear-end, engine rebuild, paint job,"... basically everything I could be using that $2970 for besides that 1 second of 20mm goodness...
And 160 man hours working in or around a prius, no matter what is mounted to it, is 159 hours, 59 minutes and 59 seconds too long around a prius.