The suspension on most of these cars is also far from normal. There's very few cars in the world which make an8 second pass on independent rear suspension. Most of these cars have straight axles and 4 link suspension.
I really want to see a Tesla Roadster make an 8 second pass with whatever tires it needs because tires alone won't get you there. They got some serious engineering in that thing to make it hit 8 seconds with a suspension that doesn't make you hate life.
x = 0.5*a*t^2 = 0.5 * 41.25 ft/s2 * (8s)^2 = 1320 ft = 1/4 mi
Under that acceleration, your final speed is 225 mph v = a*t = 41.25 ft/s2 * 8s = 330 ft/s = 225 mphThis is why you see so many approx 2.9s 0-60 times in higher end sports cars, it's hard for aerodynamics to affect it much over the first couple of seconds.
But for the first couple of seconds, you can't generate much downforce from aerodynamics because you aren't going fast enough. And there are limits to what a spoiler, etc. can generate. For a lot of street legal sports cars, this all evens out about the same way, and they end up with very similar 0-60 times.
If you try and systematically knock down all of these problems, you'll end up with a top fuel car. In that case you may get ~1000lb of downforce from exhaust alone, which gets you past the first bit while you are going too slow for the big wing to be really effective.
Now that the 2015+ Mustang has IRS, I expect to see more of them as well. I think there's already one in the 8's.
But yeah, IRS is a major pain at that power level. Most (all?) of the performance cars today have IRS, so I expect improvements to come.
The main issue I found is that street tires often just don't have the traction required, even under ideal conditions. The result is that traction control has to cut power so much that it ends up hurting the quarter mile times.
It does help tremendously on consistency and safety though. Things start to pucker when all four wheels start hazing in a 1000 HP AWD car.
You seem familiar, but for others, here's what a typical 8 second car looks like leaving the line:
http://www.speednik.com/files/2015/01/screen-shot-2015-01-26...
https://c.slashgear.com/wp-content/uploads/2015/11/cobra-jet...
http://cdn.dragzine.com/wp-content/blogs.dir/2/files/2011/11...
Notice how massive the rear tires are.
EDIT: Added picture of an 8 second all wheel drive car (GTR). The interesting thing here is the clear bias of traction towards the rear. When launching a car with that much power, the weight shifts towards the rear enough to render the front wheels almost useless (unless the suspension is extremely stiff).
https://i.ytimg.com/vi/Nf4pJZaK7P4/maxresdefault.jpg