Time to buy tires...need advise!!

AlphaT

I'm new to the forum, and all the threads and information out here is a bit overwhelming and a tad over my head, so thought I'd just ask outright.

I have a 2010 370Z Roadster Touring with Sport Package, so my back tires are a different size than my front. The car came with Bridgestone Potenza's (275/35R19, 96W on the back), 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, which I'm good with for now). 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, which rounds out the edges a bit sooner.

This is the first car I've had with "low profile" tires, and I have a few questions.
1. Is 18,000 miles normal wear for low profiles?
2. Any recommendations on tire brands/types?
3. Should I go with manufacturer air pressure recommendations? I do find that it handles a tad better with a little more pressure than recommended.

I'm not concerned about cost and ooking for what rides and handles best on highways and in corners and lasts the longest. I will forsake duration for handling, though. Any advise would be tremendously appreciated.