Obligatory disclaimer: I know frequency response graphs aren't the be all and end all of headphones, but if you know your preferences you can form semi-educated opinions based on them if there are any blatant deviations from that preference. That said..

https://i.imgur.com/0P0lYpj.png - As a former T2 daily driver guy who absolutely loved them before upgrading to their big big brother Moondrop Blessing 2, right off the bat the Sennheisers are dead to me. That near dead flat 1k-4 range, coupled with that massive bass response that starts rising right off the bat at 1k.

A complete lack of pinna gain coupled with a bass response that starts rising some 800Hz too early, coupled with that rather majestic 8-10k hill, tells me this is a very V-shaped IEM where the mids are recessed, unnatural, and muddy from bass bleed, and I'm not sure what I'd think about that aforementioned 8-10k hill, I'd have to listen to get an idea of that.

So, for me, someone who prefers a bright-neutral sound signature with an emphasis on mids & treble, I'd 100% pick the T2 over the IE 400 Pro every day of the week, even for bass-heavy music like hip hop because I struggle with the idea that the Sennheisers have good, clean, tight, textured bass with a bass boost like that.

Just my 2¢