Yes, good points & questions. I might simply need to make due with worked E7s because of budget and time. I have no doubt they will run well. I've seen plenty of dyno pulls & ets reflecting the number I'm giving. Also, our head guy has been doing this for 30 years. Even if I hit low 13s on the street, I'm good. They first Viper only did a 13 sec 1/4 mile! (if memory serves)I guess it comes down to if he's happy with worked E7's then it's a non issue. But 12's might be reaching a little unless you have some serious traction but cornering seems to be a bit more important since you've mentioned that a couple times. Do you want to go fast in a straight line or handle in turns? What works for one conflicts with the other typically.
So, do I want to go fast in a straight line or in corners? Yes! I know there is always a trade off though. The plan is to lighten the car and stiffen the suspension in the right places so that it becomes a better overall version of itself. Does that make sense? Less weight (in the right places) means that it does all of its' jobs better.