I love my IS-350. It is fun to drive, comfortable, great looking and handles nicely. The prompt response when needed or wanted is awesome when slipping into manual trans mode. Nav system is to be desired. It has some good points and I used it on several occasions to find my way but the voice recognition is worthless. Audio system is OK but it would be nice to see the track name and not just a number on CDs. Limited rear seat leg room could be a problem but I seldom use it so I deal with it. Memory front seats should be standard, after all, this is a Lexus.
Keyless entry, automatic to manual trans option is fun. Inside lighting is cool. Heat/cool ventilated seats are nice. Speed of car.
Total re-do of the nav system, especially the voice recognition. Make memory seats standard.