I have this valve but busted the vacuum nipple and now I have to email NGR to send me a new one to thread back in unless anyone hear knows where i can pick one up????? Other than my dumb ass mistake the valve is aboslutely great. It sounds indentical to the greddy type s in vta but it will throw a cel..When I went to do the single spring mod and recirc is wehn i broke the nipple so I cant vouch for the sound with the single spring in recirc but wiht both springs in and recirc it fluttered. I say buy it. Def worth the money and its very well made! I will post back with my impressions when I get it back on my car. Im running a Froge now but want the ngr back or better yet hks.. I shouldve never sold that valve......