wasnt that 11.9 on the n20 and the 12.2 on the motor? least that is what was mentioned thru grapevine years ago. as for messing up ppls tunes when i first started. 12.5 out of stock ls1 with suspension mods isnt bad, 12.7 out of stock ls1 with headers and auto isnt to bad. cars removed my tune went slower.