it' all relative to where the changes in the torque curve happen from your mods - for every mod you may gain something but likely lose somthing somewhere else.

So you lose some here - add some there.. etc... some of it is counter intuituve and balances out and that is why you don't get the numbers to add up.

I and everyone else I know have yet to every see a bunch of 10-15 hp gain mods be put together and add up.

If you get a 25hp gain, by the math on our 3140 curb - you will decrease your 1/4 mile time by .5162 seconds which is pretty good.

-marc