Hard to say. Looks too easy to be real, but they have a dyno to show for. The gain for IS350 is impressive above 3800rpm. Gain on IS250 is not that much. Someone on the Club Lexus forum dynoed it on an ISF and got no gain, so I'm really skeptical about this. I would wait for more data point. If someone else can show the gain on IS350 is as they claimed, I will get one in a heartbeat.
2010 IS350 Obsidian Black/Black interior
2003 IS300 5-spd SportDesign Black Onyx w/LSD | 4.1:1 Final Drive | Borla Exhaust | Megan Racepipe | HKS Cam Gear | JIC FLTA1 Coilovers | L-tuned Sways | Fidanza flywheel | PowerSlot Rotors | Goodridge SS Brakelines | PIAA 6600K | CDD delete | Teck kit | Gone: EMU, SRT intake, B&M shifter, TRD Grill