the quality is fine mate, i doubt you will pick up much power though,if any depending on current mods,same as any cooler they are a supporting mod not so much a power gain mod.
They are good kits mate,
If your after one, Springy Motors are distributing for them in Mel.
They have used the plazma man stuff on S14s / XR6 turbo's / VR4's etc.
They also have a great range of BOV's and intake pipes.