what were the key upgrades made in 2005 from the previous year?

 

none that i can think of

 

Generation 4 navigation with bluetooth. Not much else. That was a big one if you purchased an '04 with Gen 3 nav and no bluetooth (like me).

 

In 05, the Navigation system was upgraded from the 3rd Generation to the 4th Generation. "4th Gen" features voice-activated commands and Bluetooth phone integration.

The side-to-side adaptive front headlights became a lot more common. In 04, they only came as part of the Performance Package; in 05, I'm pretty sure they became part of the Premium Plus and Navigation Packages. Most RX's have Premium Plus.

 

Visit the Lexus website and click on the CPO tab, then model library. It should give you an idea on what's changed.

http://www.lexus.com/cpo/model_library/index.html