Have found that there often isn't any way of telling whether a mod is going to be effective on a Springer until you try. IME there's more muzzle report from .177 than .22, and more report from a Carbine than a full length barrel. If your HW57 has a full length barrel then I would hazard a guess that addressing the action noise would give the most benefit.
My .177 LGV greatly benefits from a stubby delrin mod.
I didn't think the inbuilt mod on my old .177 Lightning was doing much, until I took it off...it sounded like an unmodded PCP! However after a lot of fiddling with the action and fitting a .22 supersport barrel it didn't need any kind of moderation at all.