Not knowing the year of your RX it is kind of hard to help. Do a search for the following parts number B078NHBHBC for a oem plug and play remote starter.

 

IIRC, Lexus did not offer a remote start for the RX until 2010, which is the 3rd gen RX. I doubt if it is compatible with our 2nd gen cars.

 

 

You might want to view this video and follow his instructions on setting the up the remote starter to use your existing Lexus key FOB just like the OEM for later Lexus.

 

This OEM unit is not 100% plug and play although very close. You need techstream to activate it, otherwise it's an expensive paperweight. Had this issue with a SmartKey Camry I did one on. It also follows the same SmartKey glitch where if you open the drivers door the remote start shuts off and you need to restart the car before taking off.

If yours uses a standard key and does not have SmartKey or Proximity key capabilities (like the 2006 LS430 which has a key but can be started without inserting it) then there is zero plug and play options. I had to manually wire my 2005 RX330 for a Viper remote start and it is difficult to do.

This person is for sure using an aftermarket bypass with 3xLOCK compatibility alongside his compustar remote start so it can be started using either. Only thing I can't tell is which bypass is he using. For sure not a DBALL2/3 as the 3xLOCK functionality doesn't exit for this gen RX.