higher cornering speeds = more lateral load = more wear
Slower car = less braking, lower speeds, and smoother exits.
Plus remember, this is GT5, and I'm not sure any extra grip you extrude from a tire through setup or car balance translates to extra tire wear at all in GT5.
That is entirely subjective and depends on the driver and the car. I can drive a car with worn rears faster than worn fronts. It's something I can adjust for. A car with worn fronts just plows, eating up the cornering speed it relies on.
Possibly, but you're ignoring the negatives of having a faster car. If a car is under-steering, it's easy to manage worn rears, but that's almost never the case.
If you have rears worn more than the fronts while racing, it means your rear tires have less grip (and you're already over-steering most likely) over the length of the laps, losing more grip of your lowest grip tires on the drive wheels is no better than losing grip on your front tires if your car under-steers.
Both can become extremely difficult to manage, but in one scenario, you under-steer and exit corners with full power, in the other, you over-steer and have to wait the most precious seconds there are on a racetrack, when you should be full throttle but you're feathering at 40% waiting for grip, which is diminishing even more, because you're still bound by the lack of grip on the drive wheels only.
That's not the discussion. Of course if you add power to a car it will wear it's tires faster than it did without it. We're talking about doing the same pace; only one car (or one version of the same chassis) loses on the straights but makes up in the corners.
BTW what happened to your team mate?
Right, but it's not "making time up in corners" so to speak. It's driving through corners at the same pace relative to the cars grip.
You're thinking of it as barging through corners at 100% in the slower car, and easing through them in the faster car. But if you take the faster car through corners more gently than a slower car with better cornering, you're now losing time over the entire lap.
In GT5 I have yet to see a better cornering car wear tires more quickly than a poor cornering car with extra straight line speed. In fact it's the opposite 99% of the time.
. Best part though, just had a really close race with Green just now. My lap times were in the 39s though, best on free run is a low 38 so definitely need to take on board the advice I've been given & get those other few seconds achieved. Found that I'm quite good at holding people up cleanly on another note 
just thought I'd explain since I thought it would be quite interesting to read. 
. Managed to run a best of 35.7xx, but this tune is a bit heavy on tyres. Hopefully I can run a low 36 or better for quali', probably tonight.
