I run the saturn kit in my car. I've had my setup for 6 or so years and have only had to replace the unit once. The one time it did cook itself, was i believe due to me shorting it out while welding on the car. I make sure now to unplug it anytime I weld on it.
Mine is grounded to an external ground terminal that comes direct from the battery, and the power side comes from my master kill switch which comes direct from the battery.
I have noticed that if voltage drops too low it cuts out, typically when I have to crank the car for a long time trying to get it started when it's been sitting. I either turn the knob off to reset it and turn it back up, or I have breaker switches to reset the system and also protect it.