Early impressions with the Auricaps installed is a slightly more transparent, cleaner sound. It's more subtle than something like the Mundorfs in the S.E.X., but that was kind of what I was aiming for to keep the Mainline as neutral as possible and it's succeeded.
The sound is clean, uncoloured and incredibly detailed. I thought I detected a slight amount of harshness at first, but that's with <5 minutes burn-in so I won't read too much into it.
I'll spend some quality time with the Mainline and T1s tomorrow and report back with more reliable impressions. Based on what I'm hearing right now though, I'm not going to be disappointed!