Not sure what you mean, we don't make full headlamps?
If you mean the LED boards we make to go in the lamp, we have sold a few thousand sets over the past 2 years, and have experienced an extremely low failure rate, exceeding our internal quality standards. Any failure would not cause the whole lamp to stop functioning though...
Are you possibly referring to the sequencer modules, for the S550 tail lamp? That is a completely different kind of product, and is not related to LEDs at all, it's power control. The Mustang has a complex fault sense system which disables power to the lamp in some circumstances when it doesn't see the exact data feedback needed for the tail lamp. Luckily for all Subaru owners, Subaru still uses simple electrical systems with physical relays, where you never run the risk of the vehicle just deciding to disable a whole lamp when it wants to! There is no circumstance in which a whole lamp would go out on your Subaru.
In any case, we stand behind the function and reliability standards of all our products. Thanks!