Great ears, I can see why this works for thrash. I own many cabs, one of them the same Friedman 4x12 you have. When I've shot out that cab against other cabs, I noticed several distinct things about the Friedman cab.
First, the Friedman cab is actually quite a bit scooped compared to my other Marshall and Boogie cabs. It has firm lows and crispy highs with a slimmer midrange. It's still pleasant; not weird, but not nearly as many mids as my other Marshall cabs. Maybe this is because of the Chinese Celestions, who knows.
Second, it's inefficient. It's notably quieter than other Marshall and Mesa cabs that l own. This allows you to turn your amp up a little more and open it up. So the cab is great at making amps feel good to play.
Third, it kicks. This cab is built like a brick shithouse so it has very firm lows. It allows you to turn up the bass or depth on the amp without it getting flubby. It stays pretty tight even when downtuning.
Overall a great cab! One of my go-to's for sure.
