Which someone suggested and then I said I’d do it and then I got distracted and then I remembered again.
It’s hard to talk about the costumes of the on stage ensemble in Spring Awakening because there are so few photos of most of them, if any — and then if you look at backstage photos, if you have no other reference it’s hard to know if you’re seeing an ensemble costume or just the actor’s regular clothes. Basically the on stage ensemble wear modern clothes so that they can blend in with the regular audience members, and these outfits usually involve some sort of layering for hiding their microphones. The first national tour did a video talking about this, if you aren’t familiar with it.
Krystina Alabado confirmed that the ensemble actually have two costumes, but funnily enough she is one of the only actors for whom I have photos really proving that:
Yes I wear the same outfit every show, but we each have a winter outfit and a summer outfit that we switch out
of when the seasons change
SO LET’S LOOK AT SOME COSTUMES.
Here are photos of the original ensemble (Gerard Canonico, Jennifer Damiano, Robert Hager, Krysta Rodriguez) from opening night in December 2006:

I’m not quite sure if this outfit of Krysta’s is actually an ensemble costume, but I have a feeling it is as it appears to be hanging on the rack in her dressing room in a couple unrelated photos:

Some Broadway replacement costumes. Here’s Alexandra Socha and Matt Doyle in November 2007:

The final Broadway cast in January 2009 (Alice Lee, Zach Reiner-Harris, Eryn Murman, Morgan Karr):

The tour cast is much easier to look at because they took more pictures of themselves. You can actually see the original tour ensemble/swings (Julie Benko, Lucas Wells, Krystina Alabado, Perry Sherman, Claire Sparks, Chase Davidson) in the background of the big Totally Fucked photo:

Here’s a closer look at Julie’s and Krystina’s:

And here are some of the replacement ensemble:

And these seem to show some of the ensemble’s other costumes:

I don’t have any real good photos of any of the new tour’s ensemble costumes.
Wanna see some foreign ensemble costumes? You can see some of the Austrian ensemble in the background of one of their Totally Fucked photos:

Here’s some ensemble costumes from Japan:

And here’s the Swedish ensemble:

I have some photos of what might be ensemble costumes for the British cast but it’s too hard to say.