I own a 2013 Lexus RX 350 and converted my base, non F-Sport/Paddle Shift steering wheel into one with paddle shifters. I'm unable to import photos of the process but a lot of the work is explainable. Will add photos when I can.

If you buy the 13'-15' RX 350 F Sport wheel, it is a plug and play job. Unplug the clock spring connector and plug in the new one- that's it.

I went with the cheaper and more complicated option...

I started off with the base Lexus 4th Generation GS 350 steering wheel. It's the same as the ones equipped on the 3RX but differing in buttons. And if you do a Plug and Play job, the paddle shifters do work but the steering wheel buttons will not, as the 4GS wheel uses a different button wiring/board interface when compared to the 3RX.

When removing the wheel, I went off of MattRX's forum post, unscrewed all the wheel trims with and cut the black ground wire for the paddle shift connector and the green/brown wires. The green and brown wires go directly into the same spot, you can de-pin the connector by pushing in the little clips on the side of the connector and pulling on the wires. Plug the pins directly where they were from the 4GS connector to the 3RX connector, you don't need to pull up the connector like with removal. Then, find the black and grey wire, strip the wire and splice directly into that for the black wire (ground). Cover with electrical tape, plug in and test. If the connectors are reversed, then your down paddle will go up and up paddle will go down. This isn't an easy job, took me almost 2 hours of digging, unplugging, prying and pulling but it paid off in the end.

Wheel was $120, and it did not cost me any in extra material. The reason why I did the repinning was because I wanted steering wheel controls. You don't need to if it's not a problem for you, you can just plug in the wheel directly to the clock spring and it does work.

I couldn't find information on this anywhere- just leaving it out there for the people that want it.