i can't find on ali : lz-z02a .
**** UE , Joyroom E107, KZ ED9 are good options.
I don't know that to choose. I want something with more subbass and i don't wanna change the sound with any player.
subbass rather than midbass? warm slow rumble bass or fast tight punchy bass? slight or heavy bass emphasis? which player are you going to use?
i ask you this, because the piston 3 needs a bit more power to reach same volume than the others (it's 32 ohm, 98dB..), and other considerations.
i've listened to the **** ue and the lz-z02a a bit while burn-in, together with piston 3.
piston 3 (search for it in http://www.head-fi.org/t/478568/multi-iem-review-352-iems-compared-pump-audio-earphones-added-04-03-16-p-1106 ) and lz-z02a (check http://www.head-fi.org/products/lz-z02a/reviews/15493 ) sound balanced to my ears; piston 3 has v-shaped signature, lz-z02a, w-shaped; piston 3 has slight midbass emphasis, while lz-z02a keeps good midbass, but some more subbass (in extension and presence) than piston 3. any of both are ok for my bass needs (might prefer the z02a).
lz-z02a mids are a bit more forward than in piston 3. you can note their presence better. would say the same about upper mids (although less difference). because of this, and because of the more highs extension, z02a sounds brighter (piston 3 are not dark anyway); vocals are a bit more forward.
i wear piston 3 straight down (only possibility), not many microphonics though. lz-z02, over the ear, using the provided ear guides. both are very comfortable.
you can get the piston 3 for about $15 now, lz-z02a for $23. both are very good choices, imo. you don't need to eq them at all.
btw, my first impressions of the lz-z02a match Paulpark impressions in his review, compared with the lz-z03a. it fixes the problems of some subbass lacking, and has not the sibilant and harsh peak in high mids/trebles (6KHz).
**** ue has clearly more bass emphasis than both. but it's a warmer bass, smoother, with more rumble. its overall sound, after only 20 hours of burn-in, is quite warmer and smoother than both. sounds good, but more colored, warm, than my personal preference (i prefer thin, fast, punchy, neutral or slightly bright sound, which uses to come with good detail and instrument separation). if you like to feel surrounded by bass, sacrificing some resolution, it's a good option.
joyroom e107 has not arrived here. but you can read the good impressions it's receiving in this thread. it seems to have emphasized bass, and some highs peak (v-shape). like SilentCinema says, its sound is less refined than lz-z02a (i deduct less detailed, so), but with more bass presence. plus comfortable, at a great price.
kz ed9 hasn't arrived here either. as cheap as the e107, it comes with 2 filters (well, "normal" nozzle, and bass one). i guess you'll get enough bass with the filter. i don't expect great detail or refinement either.
summarizing, if heavy bass is not a must, i'd choose the lz-z02a probably.