Actually, the HKS on my car kind of does have the sound you are describing. Usually, under normal load, it will produce a triple "choo" sound. This is most likely due to it being re-routed into the intake and because the T-25 doesn't push alot of boost. I bet it would have a much sweeter sound if I mounted it on a lower intercooler, right behind the air dam and it was open to the atmosphere, with a larger compressor of course.