TL;DR: KBEar red foams > Spinfit CP145 > Spinfit CP360=stock=Symbio Hybrid>Sony Triple Comfort>Sony HybridWhich tips bring the best out of the GD3A? Just received mine today
I just did some tip rolling and it seems that the GD3A, for whatever reason, aren't as drastically impacted by tip rolling as their other GS Audio brethren. Spinfit CP360 sound pretty much identical to the stock eartips; CP145 have a bit more bass impact, but the high remain fairly twinkly still; the CP500, if you can get them to stay on, have the clearest treble response and slightly more air compared to stock, bass is minimally impacted and mids are brought ever so slightly forward. I tried them with the Symbio foam hybrids and found almost no change over stock. Sony Triple Comforts increased bass warmth and brought the mids forward, but at the cost of treble gain and extension, thus also impacting staging. I also tested with the DioFit Multi-flanged and Standard Leakage eartips and found they did not offer this set as much benefit as they do for the GD5 and GD7B, they also don't stay on the nozzle well unless you modify the resin nozzle or ordered your set with the metal nozzle. I think the most noticeable improvement came from the Monster Supertip Gels that I tried on them, because it seemed to improve separation and staging slightly, but I wouldn't recommend them as they can be difficult to form a seal with and they slide off the resin nozzle very easily as well. The KBEar red foams are a surprisingly good fit. They seem to improve spatiality instead of making the sound feel closed in like foams usually do. The only thing I can tell is particularly different over stock eartips with the KBEar red foams is the staging and stage size seem slightly larger, for some reason.
Eartips with short stems do NOT like to stay on the resin nozzle. This can be improved by using a knife edge file or triangular file to undercut the small ridged flange on the nozzle. If you ordered with the metal nozzle, congrats, tip rolling is loads easier for you.