Just installed these yesterday so this is an initial review. I'm recently retired from the tire and auto service business so you can bet I'm pretty picky about tires. These Primacy MXM4's replaced a set of HX MXM4's that had given good service. I found a great installer through Tire Rack that had a Hunter road force balancer and a clean, modern shop. The new tires all had the same manufacturing date of the 49th week of 2013 from a US plant. Fresh tires indeed!
I was pleasantly surprised by how well these tires balanced out. Road force variation was extremely low. One of them took no balance weight at all, the others only needed minimal weight ( 15, 25 and 35 grams total). This speaks well of the tire quality and the quality of the original equipment Lexus wheels.
The new tires drove perfectly. Absolutely zero vibration, shimmy or directional pulling. That is real important to me. I was the go-to guy for ride and alignment complaints at work. Sure glad I don't have to deal with it on these tires. I replace my own tires at about 5/32 so the old HX MXM4's were in their dry road handling prime. The new Primacy's at full tread depth don't feel quite as grippy or responsive but they are so quiet on textured surfaces and so smooth over surface imperfections that the trade-off is well worth it. I'm sure grip and responsiveness will improve with a bit of wear and scrubbing in. Overall this is an outstanding tire for this car.