Everybody always talks about the term, but nobody has a solid way of measuring it (AFAIK), so I figured why not come up with our own, and have it on a Shifted Scale.
I had the draft for the formula written down somewhere, I just have to look around and find it, but I was off to a good start that we can discuss further.
It included, peak hp numbers per $ spend, peak tq per $, 1/4 mile per $, stopping distance per $, weight per $, etc.