One problem related to brake disc pads has been reported for the 2009 Lexus IS350. The most recently reported issues are listed below.
The front brakes developed an extremely loud metal on metal sound with decreased braking performance. I brought my vehicle to Lexus who confirmed that there is a known problem and that they have a TSB on the problem. The solution requires replacing the rotors, brake pads an fins. The new parts have been completely redesigned to fix the design flaws. Unfortunately, Lexus wants to charge $600 to repair the known safety problem, despite the vehicle having only 20,000 miles.