One acquaintance I have has an older (late 80's or early 90's) Mustang in the shop for engine work. Before the work started, it was turbocharged to something like 650 hp. His new goal is 1000hp. This was 2 years ago and it is still in the "shop".
Hennessey Performance | Making Fast Cars Faster Since 1991
The previous tune was similar to this:
2015 - 2016 Ford Mustang GT | Hennessey Performance