I just bought my IS350 lilver with black leather interior, nav, ML, and lux pkg for just 1500 over invoice from mission viejo in california. If you want my advise use the service I did. Go to carbargains.com It cost a $190.00 for the service but they search six dealers and tell you which one has the lowest cost.
I love the fact I didnt have to negotiate when the car arrived.
Jeff :)