Looks great with F-sport wheels and suspension, and it firms up the handling too.
(Lexus did the track-testing and published results)
Consider the F-Sport exhaust (made by HKS for Lexus), it's nicely finished in ss, bolts on using existing hangers, etc. Sound is rich and semi-exotic and similar to the Italian Masi Ghibli (3.0L 60 degree V6 tt), sounds wicked at full throttle, quiet in cruise mode, worth every penny. I test drove a used IS350 equipped with exhaust at my dealership before buying it. Sunroof open (or convertible top down), the sound level to driver and passenger is enhanced.