When I installed the 5.0 in my StangII I didn't use the "crash switch" at first. I had a power steering line spring a leak, dumping fluid on the manifold. it's a scary thought to see the rubber isolator on a 45psi 80liter/hr fuel pump burning! After that I installed the crash switch, and moved my industrial relay to the console so i could pull it out in an emergency. I also bought a fire extinguisher that day. In short, ANY pecautions you can take to keep your ride from going "up in smoke" is worth the time.