No, it has a timing chain.
The 2007 Lexus IS-250's engine produces 185 ft-lbs. @ 4800 rpm.
The 2007 Lexus IS-350's engine produces 277 ft-lbs. @ 4800 rpm.
The 2007 Lexus GS-450H's engine produces 267 ft-lbs. @ 4800 rpm.
The 2007 Lexus LS-460's engine produces 367 ft-lbs. @ 4100 rpm.
The 2007 Lexus RX-350's engine produces 251 ft-lbs. @ 4700 rpm.
The 2007 Lexus ES-350's engine produces 254 ft-lbs. @ 4700 rpm.
http://www.clublexus.com/forums/showthread.php?t=338155
The 2007 Lexus IS-250 has a V6 engine.
The 2007 Lexus IS-350 has a V6 engine.
The 2007 Lexus ES-350 has a V6 engine.
The 2007 Lexus LS-460 has a V8 engine.