My take is anyone who has one is 100% satisfied GM got it right! I, for one, doubt I could ever tell the difference if it had any more HP. And, if you think about it, the ONLY time you "might" feel that HP is at EXTREME performance situations! And that is a rare situation to be in. Most likely, anyone who IS in that position very often will modify it minimally with bolt ons and take it to the 10's. Limited internals and you are in, what, the 9's?
But I'm really really happy with 11.8-12.3 at my disposal anytime I want! HA! With Traction Control thank you!
I'm blessed to have one. Bottom line. I'm Grateful GM made it, grateful for my buying experience. Once in a generation opportunity! The car is an instant classic and family heirloom!