Use exactly what is recommended by Lexus as listed in your owners manual.
The 2008 Lexus IS-F's engine produces 371 ft-lbs. @ 5200 rpm.
The 2008 Lexus IS-250's engine produces 185 ft-lbs. @ 4800 rpm.
The 2008 Lexus IS-350's engine produces 277 ft-lbs. @ 4800 rpm.
The 2008 Lexus GS-450H's engine produces 267 ft-lbs. @ 4800 rpm.
The 2008 Lexus RX-350's engine produces 251 ft-lbs. @ 4700 rpm.
The 2008 Lexus LX-570's engine produces 403 ft-lbs. @ 3600 rpm.
The 2008 Lexus LS-460's engine produces 367 ft-lbs. @ 4100 rpm.
The 2008 Lexus GS-350's engine produces 274 ft-lbs. @ 3600 rpm.
The 2008 Lexus LS-600H-L's engine produces 385 ft-lbs. @ 4000 rpm.
I have a 2008 ES350 that has had the oil changed twice. The receipt shows 8 quarts which in my opinion is a lot for that engine. -------------------------------------------------------- From the owner's manual for a 2007 Lexus ES350, it is 6.0 qts (5.7 L) without a filter and 6.4 qts (6.1 L) with the filter. Uses 5W30 oil.
The 2008 Lexus IS-350 has a V6 engine.