OK, so I've owned the GR07s for about 9 months or so now, and I love them. I've been using the Sony hybrid tips that came with the IEMs (when Vsonic still gave you 10+ tips with the GR07 (the ones on the left):
I've never used any other tips because the GR07 stem is fairly narrow, and most other IEM tips are slightly wider and aren't as secure.
Well I recently got the Havi B3 Pro1, which came with some fairly narrow-step tips. I idly decided to try one of the white silicone-ish tips that came with the Havi on my GR07s, and noticed they fit quite securely and well. They also have pretty much the same stem length as the Sony hybrids, meaning the edge of the tip is as far away from the nozzle. The main difference is that the Havi tips are wider bore, and they are actually "createred in" or carved out in the center (the Sony tips have a sharp edge around the sound hole), and don't focus the sound pressure as centrally as the black Sony Hybrids:
With the Havi tips, the GR07s suddenly have an incredible soundstage. I never knew the GR07s could sound like this. Still as detailed, but rather than the razor-sharp transient focus, they now sound wider, and ever so slightly relaxed and diffused, and with better depth perception, and an even more open feel, to the point where there's no sense of inside or outside head, well-recorded orchestral music sounds utterly holographic and convincing, surrounding you. Admittedly I'm using my most linear pair which has a slightly milder 6K peak and slightly fuller midrange, but I'd imagine any EQ response would still sound wonderful.
Songs I've listened to 100s of times suddenly got that emotional context, the bass even deeper and bigger as you can better feel the room sound of it. I'm so used to the GR07 being to absolutely "hard" and clinical and sharp, this is a great surprise and an invaluable tool for me for getting a different sound from them.
Those who may own both the GR07 and the Havis, try this and report your findings, I'd be nice to hear others impressions on this combination.