The real HKS ones are suppose to have a holographic HKS logo. But I don't believe the old HKS BoVs have holographic logos.
As for Tial, I like the brand, they are top notch, but I just don't like the sound of Tials. It's more of a smooth rush, opposed to the HKS which is more of a whistle. I do like Greddy valves though, which is a mix of the two. Turbosmart is also pretty damn loud. To each his own though, BoVs are just personal preference between the brands and sounds, no real advantage over each other.