Wes Siler of Jalopnik hails the ZR1 as being incredibly refined. So far, I've read the Auto Week and Motor Trend reviews of the ZR1 press day, but I think Jalopnik's was the most enthusiastic. Motor Trend seems to feel obliged to be predictable. Auto Week's article almost seemed plagiarized, especially in the beginning.
http://jalopnik.com/5037293/2009-cor...r1-first-drive
The ZR1 supposedly has a little bit more left in it in terms of a 'ring time according to Mero. I think we can all see that the ACR could shave a couple of seconds if the driver were more familiar with the car at that track. Add more appropriate gearing (not necessarily 'ring specific though) and I shudder to think what kind of time the ACR would set. 7:17 maybe???