Think I found the section you're talking about Streeto, you'd have to show me one day...I get the feeling it was @Geoff
Those invisible barriers are VERY reminiscent of the old course maker...
There is a decent section down the bottom, suitable for any horsepower.
If you go reverse from the pits, it's the few corners right before the third bridge you come across.
It will take you a couple minutes to get down there, as it's pretty close to the bottom end.