That's the issue Mark, not many cars have a good enough setup to attain those sort of figures, and that's why it got a bad name. Stock manifolds or 3 inch exhausts aren't going to cut it, we are talking 4 inch system here, and how many would run that on the road.
I can say after running both the GTX3076 isn't quite as responsive as the 71 but spools in a similar fashion, with approx. 40kw higher potential imo.