Originally Posted by nightfire

The following I copied from 370ztune.com website about the Stillen Gen III (hope you don't mind Hunter)

The power result: A dyno-proven 18.5 horsepower gain at the wheels on the G37 Coupe and 17.5 horsepower on the 370Z. This translates to an estimated 20-22 horsepower gain at the flywheel! For G37/G35 Sedan owners, gains are 14 horsepower at the wheels. No other intake for the VQ can match these power gains!

But note that this was probably the MAX gains they ever saw on these cars with this intake, unlike the above mentioned numbers for the HKS which are an avg, so I'd say they are probably right about the same or maybe the HKS are just a few HP shy. Now lets throw the JWT Duel Pop Intake into the equation!

Note: Nm I found the WHP on the JWT and it says 6.5-10 so it's still looking less than the Stillen. The only think with the Gen III that I don't like is the fact that they wrap all the way around and therefore cleaning the filter is a pain. Also they might not work too well with a body kit but I'm not sure, anyone know?