firetruck41, have you noticed any reduction in output compared to when you first installed them? Can you compare with a fresh bulb? As for durabilitty, it's excellent! Of course OEMs can last many years, but this at least tells us the brightness increase is not made at the expense of durability...
As a side note,
those bulbs are available in H4 format in 60/80W with both low and high beams HIR in the same bulb, for those who have combination setups such as the JDMs and older landcruisers, but the price is quite steep at between $50 and $60 a bulb in sets of 2...
As for myself I just installed standard type (halogen) overwattage H4 bulbs when one of my orginal Japanese bulbs failed and at 100W these replacements, which cost me only something like $10 a set when I got them on special from Princess Auto last year, are visibly better than the regular 55W bulbs and silverstars and work perfectly well in the standard wire harness and 15 amp fuse (which can sustain 15Ax14.4V or a bit more than 200W).
When installing replacement bulbs we often hear about the necessity to install relays, thicker wire.... But the limiting factor reducing voltage is NOT the wire gauge, but the cleanliness of the connections, and, what is often forgotten, the cleanliness of the reflector housing itself! In other words, the condition of the connections in the circuit and a clean reflector and lens is more improtant than upgrading your wires and installing relays...