Custom IEM or TWE

[deuter]

I’am current using Grado GT220, I used to have JH13 custom iem many years back.
I recently got a Fiio Q11 and am looking to invest in a custom iem but not wanting to spend over $1000 if I can yet beat the sound signature of the JH13.

Any recommendations on what I should be researching.

Thanks for all your help.