Yeah, I agree with the looks, but don't hold the bubble complainers at fault, because I was one of them.
But I drive my car between at least 80 miles a few days every week. There are no days that I don't put at least 40, and plenty of days that have me going upwards of 140.
With that kind of mileage, the low profile of the car (which took some getting used to) and my kind of ADHD, always in a rush lifestyle, there's going to be some issues with the 21s. For me the last straw was driving over a recessed manhole cover in DC and popping a tire. That would have been the third 21 I replaced, so instead I just went ahead and put the 19s on.
I know I'm stepping on my sale a little bit here... But it's only fair that people know this stuff.
If you drive your car because you love the Sunday drive on well-maintained rural roads (I'm looking at all you folks from Arizona and Utah and Montana and Wyoming with no small amount of jeolousy), the 21s are going to be awesome.
But I got this car ('22 GT) because I drive 25,000 miles/yr and I wanted something nice to spend all that time in. And the used market cut the price in half for me, making it affordable ($65K w/11K miles on it). But I couldn't afford replacing tires, or even getting a flat while working (for work, I have to be at court on time; thankfully the one flat I got was on a Sunday pizza run).
So yeah, for all the reasons Cosmo provides, these tires are awesome (the ride is sooo smooth too). But there are downsides.