From the look of the pic that unit looks like some I have seen advertised for non ABS cars.
I have a stopper on my '90 model na
with ABS, and it actually does slightly firm up the pedal.
That's only reason that I know for fitting one.
When I originally looked at getting one, it appeared that most available did not fit ABS cars, so I made my own.
A fairly easy job with no need to drill any holes etc, and wasn't too hard to clear all the ABS pipes.
It mounts in 3 places. On the 2 side bolts that hold the ABS mounting bracket, and a stay out to the side on the wheel well.