It is very common for standard Toyota valves to break at the tip of the valve when the engine is pushed hard, dropping the valve down the cylinder bore which could cause a large amount of engine damage. These uprated valves are a lot stronger than standard valves and we are yet to have any break on us in any of our race cars. They are rated to a lot higher RPM than standard valves so if the engine gets over revved there is a lot smaller chance of causing any engine damage. These valves are also flat faced rather than the standard dished ones which will raise the compression ratio of your engine slightly. We use these in our race 2ZZ engines in our Lotus 211 race cars which are around 270bhp.