I'm not entirely sure, GR07's driver is no slouch, it's the shell that is problematic - and the recommended very deep fit.
Hifiman drivers are better, but it seems to be impossible to remove them from their shell without damage - I don't know how to do that, I've tried numerous times.
Those are glued in by the annoying chinese hotglue, without any protective metal casing.

MTPG/MTPC is probably not really better, it doesn't have the detailing, but might be there's something to be done about it. They are only improved matching versions of Turbines.
Sennheiser IE8 driver is better, Hifiman RE-272 driver is too. IE800 driver might be a bit better as well. Same might go for RE600, which I haven't heard yet.

See, 50% of the work at a dynamic driver IEM is in shell and tuning via filters and venting. This is where GR07 fails, not at the excellent driver. It's easy to check - just remove back of the shell and hear a major improvement already. It's possible that newer VCO2 can be improved considerably too by modding the shell.

The ringing at 6.3k is nicely reduced with the eq as well, but not completely eliminated. Bass still sounds bit choked (too short decay at lowest parts) despite correct volume - the driver is struggling in a too small shell or the lack of perfect fit causes this issue.
Note the difference between shallower but good fit and deeper but "clutch" almost fit. The seal means the bass sounds much better (still slightly choked due to limited chamber size) and no need of bass adjustment means I can use the spare parametric at the highest end. Plus the deeper eq cut at 6.3k means ringing is yet more reduced, still bit audible though. W/o eq the shallower fit sounds atrocious though due to that peak.

These are way better driven by the Leckerton than FP10 for some reason, perhaps smoother treble.