Have you gotten the Escudo Pike's Peak car yet? I widdled the 1/4 mile time down to 8.5x @~200 mph! That trap speed should be good for 6's but I still can't get it to hook. It took hours of suspension tweaking and passes to get the 8.5 et. My F094H formula car is almost as quick but it traps way lower. I think my best with the F1 car is 8.6x something. It barely spins at all.
Also, I too hope you can S/C American cars. And that the drag racing is a bigger part of the game.