Something about that SIU's last sentence - "More bangs doesn't always equate more power."
Maybe Chang is more pwerful than Viole, but can control only 2 or 3 rooms, or maybe Quatro isn't defeated yet.
I somehow can't see Chang being stronger than Viole (Viole put a scratch on Urek after all while protecting Miseng), but it could be a good fight and a fair bit closer than might be expected.
About Quatro, I'm just saying it's possible. If Baam has a method of recovering from injuries, there are bound to be others too. Although I hope that lobster is not something common or accesible to people like Quatro.
I highly doubt Chang is stronger tbh, but we'll see, Viole still has many tricks up his sleeve like the lobster. SIU just stated something we've pretty much always known, more bangs doesn't always mean more power. But considering the shinsoo ranking test, Viole was already far above the average regular and considering how his growth rate is much faster than everyone else's, that gap should be wider after 2 years. Viole not only has the advantage of being able to use more bangs than other regulars, but he also has the power. You have to consider that Viole isn't Chang's only enemy, if Viole doesn't feel that he can take him on by himself then the whole team can just attack him, there's no way he'd be able to take down the likes of Devil Arm Teddy, Viole and Yihwa whilst Prince and Goseng are using their lighthouses to slow him down. Viole won't risk losing the test and getting his friends killed just because of arrogance.