I just ordered the RX350 kit from Phil. Will have a very detailed write up when installed. It is my understanding, and why the kit is so great, that you do NOT have to separate the actual lens. All you do is cut that back part off and it's pretty much a direct bolt on. This back part is much easier to seal and no lens cutting involved! The FRX kit is similar but there is some cutting of the internal projector holder mounting posts. FRX is cheaper with similar performance but some cutting involved.
Your OEM headlight bulb will not fit. RX350 projectors are true Lexus OEM HID projectors. They will require an HID kit to work. I recommend the TRS Sierra Spec kit but if you do the RX350 projectors you will need to get D2S HID bulbs and leads. Phil can hook you up with all the right parts in one easy step.