My personal experience has been this. I never weighed the car(removed the tire,jack,frt sway bar after the CAI). Its a Deluxe GT,side airbags,int upgrade, only options,MT.
Bone stock the best I mustered on the P Neros was a 13.55. I added CAI,tune,4.10s on PNeros I couldn't get past a 13.0 and with 4.10s had nasty wheelhop.
I added DRs,LCAs and could hit 12.7s with good prep and DA. Delete plates,UDPs,UCA,rear axle brace I hit a 12.56.
I think with my current 15" wheel combo I could have hit 12.3s but that is bench racing so who knows??? Then I added a Whipple.
Now my best is a 11.80 on 10 lbs. I can't shift at upper rpms till I add tq limiters. Moving to a 28" rear tire my LCAs are now out of line and I need relocation brackets. Man this drag racing stuff is so frustrating and fun at the same time! lol
I was going to stay NA with cams,heads,LTs, then the Whipple deal came along and I jumped ship.
I can say these cars are very weather dependent. Heat soak, high temps,nasty DA suck the life out of them. Thats why I stopped comparing my times to others, WAY too many variables. I just know I hate East Coasters like Spaz in the fall!!! lol