For me with the LBBS the difference between no foam and donuts is pretty huge. It must be either because the holes on the backside of the case are blocked or because the foam just creates a better seal. Without foams the bass is pretty weak, but with foams I am surprised about the level of bass buds can create (even if it might not be bass head level, it’s much better than with open back over ear headphones).
Second impressions are definitely much more positive. Good Bass, good treble and air… pretty good resolution for 50$. There are things about the tuning I don’t like, but that pretty much just boils down to personal preference in the end. I can definitely see how earbuds are a viable alternative to IEMs. Will probably compare them to a couple of IEMs over the weekend and am curious to see how it stacks up against them.