100 pound loss = how much HP gain???

If traction is an issue it depends on where the 100lbs comes from. If it's from up front and the car is rwd, removing 100lbs will probably help traction and give you more bang for the 100lb reduction. Just the opposite if the weight removed was inside the back bumper.

Grant
I think the Op was looking for a direct answer of how much horsepower you would gain for LOL for a hundred pounds of weight loss...
And this is almost in my opinion a trick question..
The obvious thing people are going to want to know is the current ET..
It's my strong opinion that once the ETA gets down to a certain level these hundred pound are affected at different levels and as you are pointing out in different places in the car as well...