hello stang world just wondering if flow cats are worth the investment?

 

Hi-flo cats may not work well enough if you have OBDII inspection in Illinois. Sometimes you can get P0420 & 0430 codes (low cat efficiency). Sometimes anti-fouler extensions work, sometimes they don't.

However, Kooks Headers sells what they call "Green cats". I replaced my hi-flos with them and codes went off and have stayed off. Passed inspection with flying colors. They are a little pricey though but they are top notch stuff.

 

did u feel like like u gained performance from them?

 

You gain a little bit up top over the stock converters, but nothing earth shaking. Hi-flo's are usually used with headers when the stock mid-pipe and converters won't fit anymore. I wouldn't just replace the stock converter(s) if everything else is stock.