code111japan 4 I installed it on JZX110 (1JZ-GTE VVTI) and it doesn't open on low RPM and little throttle when driving normally so there is turbo stutter / surge. Seems that spring is too hard and putting it on softest settings doesn't help. On 1JZ, when mounted on the original location, it is far from vacuum source so that could be the problem too. I tried different hoses and now I'm using silicone hose. Since it's JZX110 and electronic throttle, it probably doesn't close throttle entirely so there is not enough vacuum to begin with.Build quality seems nice and feels expensive. I didn't notice any boost leaks but I didn't test it properly.Sound is quiet and a bit "boring" but you can hear it just enough (way quieter than Blitz blow off). Perfect for every day.I'm using it every day so we will see how is durability.