Back on topic, and to clear up a few things.
1) The mono springs used in the current C7 vettes are made of plastic/composite, and also act as anti-sway bars to some extent, so those can be smaller/lighter. The Z06 version does not use coilovers.
2) Extensive lightweight materials are used in both the base car, and even more so in the Z06 version, and the upcoming ZR1. Things like forged suspension control arms, and magnesium engine and rear transaxle subframes. The hood and fenders on the Z06 and ZR1 cars are super light CF, and there are a few other panels IIRC... The rest is fiberglass over a hydroformed aluminum perimiter frame for the top end cars, and hydroformed steel for the base cars. (Hydroforming is very high tech, and works quite nice as you can vary the material thickness and many other nifty tricks to make it strong, yet light as possible.)
3) The pushrod motors are not dead. Anyone notice that the acuators for the V4/V8 engine modes are in the LS9? I did. That means at highway speed, or under low load, your V8 becomes a V4, and the fuel economy goes way, way up. As for an engine like the LS9 that is rumored to be capable of 650hp, but will likely be sold as only 625hp... Hello? You need more than that amount of power stock eh? Look at the design. It has cross bolted mains, twin gerotor oil pumps, a semi-dry sump oil pan/system and built in oil cooler. The motor is very space wise, and will fit under or into most anything on the road.
Now, would I rather have a R8 with only 420hp, or the ZR1?
Totally depends on what I wanted to do. The R8 would be a better DD, and across the country car. It has AWD, better interior by a 1000% and will turn heads no matter where you go.
The ZR1 would be faster on the track, and probably get better gas mileage, would also turn heads in the right places and the interior has improved greatly from what it was, but the seats still suck, and there is no excuse for that from GM on a car of this type. (For this price, they should offer seat options/upgrades, and do it with a company like Sparco for example, or Recaro..)
The Vette also needs to offer a automatic/manual that is on par with what is out there right now. (Advanages of that would be better gas mileage, and only one transmisison needed across the board for the whole car line.)