I have a bunch of Grado's and have enjoyed modding them and will probably keep on playing around with them but I want to try another kind.
I have a Musical Paradise MP-301MK2 tube amp and mainly use it for speakers even though it was first thought of as a headphone amp.
I like nice tight bass, not thumping, just clean deep as I can get bass thats fast and clean. The highs and mids overall ideally willl share the same tonal attributes, so basically even tone wise all around, I have several IEM's that are excellent at reproducing nuance and detail with all around great sound but lack that emotional toe tapping hard to describe thing that make's an IEM like a UE700 sound as good or better than an IEM like a Sleek Audio SA-6 thats dead on all around and fun to listen to but lack that tiny little extra thing that gives IEM's like the UE700's which cost about 1/2 as much a bit more involving sound. I want nice say -max. $500 cost wise- full closed over the ear headphones or similar even like an open one ala HiFi man HE-4,5, I'm looking at maybe doing a custom Manufaktur version of some Beyerdynamic phones 770's maybe I really have no idea as I haven't heard anything but Grado's and some Ultrasone OZMA phones which do not do it for me anymore.
Amp will be Schiit ASGARD or VALHALLA depending on the headphone I select as I believe either will work with my current stable of Grado's. Please recommend some, tell me I'm on the right track or totally missing the right path here...Thanks guys.

I need impedance direction also, am lost about all that stuff....