Nissan 370Z Forum - Newbie from Oklahoma

I live in NE Oklahoma and drive a 2010 Nissan 370Z Roadster Touring with the Sport Package, 7-speed automatic with Downshift Rev Matching. She's silver with a black top and named She-Ra, Princess of Power. Love, love, love my girl!!

It's time for me to replace my back tires (front tires different width), and I joined this forum in hopes that I could learn which brands/types have worked best for everyone. The car came with Bridgestone Potenza's (275/35R19, 96W), and after just over 18,000 miles, they've worn down to 4/32nds on the left rear and 3/32nds on the right (both front are at 6/32nds). I'm just a city/highway driver. I don't "play" in the car or spin my tires, though, I do like taking corners at a higher than average speed. Is this normal wear for low profile tires? Any recommendations??