Both, learned responses - thank you.
But I think, and this is not to say that I really disagree with what was said - but race cars, at least professional ones, aren't really "tweaked" to within a hair of exploding/crashing etc. Given what a team costs to run, and the liability exposure of killing a driver, or worse people in the stands, and just simply the coast of a car, yes engines are quite often treated as consumables, but aerodynamics are typically wind tunnel tested not only for desired effects, but also potentially instabilities. I guess what I'm feeling discomforted by is the experience of when aerodynamic shaping became the norm during the 80's: it seemed that it didn't matter how many hours one spent in the tunnels, how many millions of dollars one spent in achieving the desired effects and still giving one sufficient engineering margins: "stuff" always happened. The case that comes to mind immediately was the nose/chin spooks which provided the front-end down-force. All the tunnel testing never hinted at the problem of having another car in front of your car, dirtying the air, negating the necessary down-force and turning the car into a lifting body. Fine, nobody saw that one, and all the teams went back, spent further millions on building margins in again given that contingency; only to discover that being the center car of three running side by side, could generate equal unforeseens. ... in the spook community, one thing they teach is: it's not what you don't know that'll kill you, it's what you know that isn't true that will, ie, it's when you think you have all the bases covered and aren't paying meticulous all the time to everything, double and triple checking assumptions, that the unexpected happens; and like I said before - at TGV or champ car type velocities (not all that different), when things go bad, they do so very quickly and very badly. We saw problems with tire dimensions changing with speed and temperature; we saw such little things as aero surfaces becoming wet from rain and losing laminar flow; we saw subtle changes w/re even such little things as the shape of the driver's helmet, and where it sat in the airstream. My concerns w/re the articulation might even go to the level of wet track vs dry track and the rolling resistance, or worse some wheels seeing a dry track and others not, where one could see some type of self-reinforcing behaviors introduced, and without the dry track level of friction, might no longer be self damping.
As you point out, the increase in speeds has been incremental and over a long time... but even so, just from experience, mother nature does seem to have a profound ability to toss a monkey wrench into the works, especially when one is least expecting it.
Again - thanks for the learned responses - greg