Hi everyone, just an update. I ultimately ended up purchasing a 2008 C6 Z06! It has 22k miles on the chassis and 1k miles on the motor, after the previous motor suffered a bearing failure. The replacement motor is newer and supposedly outside of the range of the valve issues. I have a 2 year warranty on the motor that transferred to me when I bought the car, so for now I feel pretty safe with it.
As for the car: it's obviously a much, much different beast than the FRS. The straight line power is incredible; I can press the gas in almost any gear and the car is sent hurdling forward so quickly I can barely process it.
However, I do have several complaints about the steering. First of all, the steering is numb, as the reviewers complained about. In the FRS, I had direct control over the front wheels. Every little groove on the road or feedback was transmitted to the steering wheel of the FRS, so I knew exactly what was going on up front.
In the Corvette however, it seems the power steering is much stronger. The wheels can be hitting grooves or experiencing bumps but you won't feel it in the steering wheel; you just have to hold the steering wheel and trust that the car will go where you're pointing.
Also, the Corvette's steering ratio is terrible. When I was taking corners at the track, I had to turn the wheel so much my hands were hitting my knees. And everytime I had to counter-steer, I felt like I had to spin the wheel like how people spin those wooden boat steering wheels you see in old pirate movies. The FRS, on the other hand, had a much more linear steering ratio and was much easier to handle that way.
The oversteer of the Corvette is pretty fun though. You give it a bit of gas and the rear steps out fairly predictably. While I never took it through corners faster than 100 mph on the track, I will say that it's fairly predictable, and you can catch it fairly easy as long as you're really gentle with the throttle.
The car understeers going into turns, but I think I can fix that with an alignment.
Anyway, I know it sounds like I'm E36 M3ting on the car, but I don't regret it at all. It's fun, in a different way than the FRS. That being said, I think ultimately I might re-visit the FRS platform some time down the road. Owning the Z06 has given me so much more respect for the amazing engineering that went into the FRS steering feel and its agility and overall driver feedback. The FRS is as fun as the Z06, just in different ways.