This is my first Lexus and curious to know what parts are shared with other cars from both Lexus/Toyota. Engine, tranny?

 

I'll take a quick stab at it.

The RX uses the new 3.5 liter, designated 2GR-FKS. This engine is also used in a RWD layout (longitudinally mounted) version in the new 2016 Toyota Tacoma and the 2016 Lexus GS350.

The 8 speed transmission (U881E, U881F) is brought over, I believe, from the 3rd gen RX350 F Sport. I am not aware of it being used on any other Toyota products.

It uses the Toyota K Platform, so I assume it shares some chassis bits with other K Platform vehicles (Avalon, Camry, Highlander, Sienna, Venza, ES).

Other than that, I'd expect to find common items shared with other Toyota vehicles, like sensors, switches, etc.

 

Somehow somewhere, all Lexus parts share with toyota. Its why they are soo damn reliable.

 

Toyota/Lexus have had the same power window buttons for 30 years. It's truly amazing how reliable that part must be.