I've had to send a few of the boxes back for repairs, but never any problems with them after that. I have an MSD distributor and box in a toter I built that has well over 100,000 trouble free miles on it now!!!!! Not many of the stock units will hold up that well, let alone work as good as this does.. I also still use the same crank trigger system on my big blocks that I originally bought about 10 years ago and have switched it to numerous engines over the year, it's never missed a beat yet!!!!