OP here. The brakes have been fine. I did rear pads a few weeks back. No issues with the front since that pad & disk replacement. Knock wood.

Now trying to track down what I think is a bad wheel bearing but that's another thread.

 

where is the extra row of air slots?

 

Here's how you know that the different part numbers don't matter for those rotors. Go shop for rotors at a place that specializes in brakes. I use a large vendor in California (I'm not pimping for anyone, so I'm not mentioning the name) and ask them about rotors for your car. They don't care if it's built in Japan or Canada.

By the way, while you're there, maybe even buy a set of rotors from them. I used to use only OEM Lexus brake parts, and they're okay, more like a known quantity. If that's what you have now and you liked them - tough to be disappointed going that route.

But the fact is, like many, MANY overweight CUVs (which often carry over mechanicals from the much lighter sedan platform they're built on) they're woefully under equipped for real braking. But maybe that's just me - I'm super picky about noise, dust, warping, fade, and pedal feel. But I'm a performance nut, with both toys and daily drivers, and the RX is sort of neither - it's my wife's car, so there are limits to what I can do to it. Still, without upgrading the whole system, a better rotor is out there. Trust me.

Now, the Lexus OEM pads - they're remarkably dust free. If that's important, buy those. More performance almost always requires dust. Yeah, to varying degrees, but it just does. Yes, that's a vast oversimplification, but you don't get something for nothing - it's all a trade off, whether it's dust, noise, rotor wear, temperature characteristics - you can't have it all.

And oh, by the way, Toyota is famous for changing part numbers over the years, so that's always a nice twist. Try and download the Toyota EPC on the interwebs someplace, and you can get a history of numbers for the part you need, as I recall.

 

So, for quicker and cooler stops with longevity, something like the StopTech slotted rotors (not drilled) and maybe Centric/StopTech, or similar ceramic or hybrid pads to go with them? The upper end pads all claim to be silent, clean and long lasting.
Not trying to shill here either

 

Mine have also been working fine since installing them in March. I went with Raybestos hybrid EHT pads and they seemed to work well. One thing during install was that the rotors were TOO beefy and I had a hard time getting the caliper bracket with pads back on. I eventually took off the pad plates to get it to fit, and even then it was really snug. I had to clamp the pads to the bracket while lightly tapping it into place. Not sure if you had the same issue but it could have just been the Raybestos EHT pads being too thick also.