The RX350 requires a minimum octane rating of 91. Only the RX300 and RX330 models can take 87
The 2007 Lexus IS-350 runs on premium unleaded (required).
The 2007 Lexus IS-250 runs on premium unleaded (required).
The 2007 Lexus ES-350 runs on premium unleaded (required).
The 2007 Lexus GS-450H runs on premium unleaded (required).
The 2007 Lexus LS-460 runs on premium unleaded (required).
The 2007 Lexus RX-350 runs on premium unleaded (required).
For the 3.5 six 87 octane and I think both hemi's take high test. Stock, both Hemis recommend 89. With engine tuning and performance chips, you can bump up to 91 or 93, but Dodge doesn't recommend that octane while stock.
regular unleaded - 87 octane
93 octane
The 2007 Lexus IS-250 has 24 valves.
The 2007 Lexus IS-350 has 24 valves.
The 2007 Lexus IS-350 has a V6 engine.