Looking for a compliment to my Beyer DT770s, contemplating Denon D5K, recently thinking Grado maybe

So the upgrade bug has bitten hard and I have some credit card rewards burning a hole in my pocket. I got my Beyers (DT770 pro 250 ohm) about a year ago along with a Fiio E7/E9 combo. I love the clean clear highs from the Beyers and the impact of the bass. I listen to a lot of electronica and dub-step these days along with hip-hop and top 40. Rock was my first love though and it brings out the weaknesses of the 770s. I also spend some time with classical and some good epic soundtracks.

When I first did research I wanted to go the Denon route but I couldn't get the cans and an amp setup at the time. My first instinct when the upgrade bug bit was to pick up some D5k's but the more I read about them their strengths tend to line up with my Beyers. Ive been thinking recently that I might want to get a pair of Grado SR60i's and see what THE rock headphone brand could do for me and I could use the extra money Id be saving to get an entry level tube amp and DAC.

I'm open to suggestions. I don't want to spend more than 450 not including money Id get from my Fiio's If I upgrade in the amp department.

Thanks in advance

Long time lurker, newly active member

Why the SR60i and not the SR80i or even the 225i? Is it simply to not be too far in the hole if I don't end up liking the grado sound? I don't mind reselling If I don't like them but I don't want to love the SR60s them and wonder if id like the 225s better. I read one review which claimed the 80 and the 225 only had slight differences rather than an extra wow factor comparable to the doubling in price. Reading reviews about the 225i I really want to try it out. I think Ill save the denons for another day. Save them for a time when I look to upgrade from the beyers as they both seem to shine with the same types of music.

Just picking the cumulative brain of headfi and seeing what I get

Bump... close to taking the plunge with the 225s. checking for some last minute advice