Extended Warranties are one of the most profitable products that automobile companies sell.
I considered an extended warranty due to the Hybrid technology but decided to wait and see since the standard warranties are really good. (By the way, dealers don't like to tell their customers this, but you can buy an extended warranty at any time as long as your car is still under warranty.) I've just pasted a short synopsis of the warranties (go to http://lexus.com/models/warranty_vehicle_p...tion/basic.html for full details).
Basic Warranty - There's no way you can expect the unexpected, but you can definitely prepare for it with the Basic Warranty. The coverage lasts for 48 months or 50,000 miles, whichever comes first. Wheel alignment and balancing, however, are covered for 12 months or 20,000 miles, whichever comes first.
Powertrain Warranty - The parts of the car that do the heavy-duty work need a heavy-duty warranty. The Lexus Powertrain Warranty lasts 72 months or 70,000 miles, whichever comes first. Except for the situations listed on the Basic Warranty page, this warranty covers repairs needed to fix defects in materials or workmanship of any component listed below: (http://lexus.com/models/warranty_vehicle_protection/powertrain.html )
Hybrid Warranty - Hybrid Vehicle System
Coverage lasts for eight years or 100,000 miles, whichever comes first, on Hybrid control module, battery control module, Hybrid vehicle battery pack and inverter with converter.
With these warranties as standard and no additional cost, I decided that I could be paying a lot for an extended warranty and would actually be getting very little additional protection. And if the RX400h models do start to show any serious problems, I can always buy the extened warranty before my car runs out of its standard four year warranty. JMHO