You might not have seen it obviously mentioned since it's a standard feature and not something you need to select, it's part of their smart access system. Did you search the Lexus website? Took me a minute to find that.
SMART ACCESS
The SmartAccess* keyfob lets you lock and unlock your doors and start the push-button ignition—all without having to take your keys out of your pocket or purse. As soon as the sensors detect the presence of your SmartAccess key, the door unlocks when you touch a front-door handle.
STANDARD ON: RC 350 F SPORT, RC 350
But there's no hard system you can get installed through your Dealer? Strange...Never mind I found it. Remote start is done thru the Lexus Enform App, unfortunately only available on IPhone & Android (I have a Windows Phone).
Correct. On a car with a physical key, you still have to insert the key and turn the ignition on or the car will die when you touch the brake. Since the RC is push button start with a proximity key the only way to do this is to kill the car and re-cycle the ignition by pushing the button to start it againthe reason is because remote start is basically a circumvention of the ignition system, for the car to work proper it needs proper ignition procedure...