OK... reporting on my replacement Battery since something has happened.
It's been about 4 months now and in the last week, my Pre3 has been driving me crazy when I put it on the Touchstone... it kept loosing it's charging contact and doing the "ding" sound over and over.
I rebooted the phone a few times, pushed it, moved it, and sometimes it would be back to normal and simply sit and charge (and stay charged), but for the last two days... no more, it barely could managed to charge before the dinging starts.
I figured maybe the contacts were dirty, cleaned those. Maybe it's misaligned, pushed and applied pressure (which appeared to help a bit but never for long).
So I searched online about Pre3 and Touchstone having issued... first thing I found was a mention of "battery swelling" and yep... that was it.
I took it out and replaced my original battery and everything is fine again (for the last hour... ) no dinging so far.
The "new" battery is no longer flat, and has a very noticeable curve on both top and bottom, I'd say close to a good mm per side.
I just send the store an email, couldn't find anything about them having something for this battery's warranty, but found a general mention of 30 day money back, or 3 months replacement, but at 4 months...well, that's a bit sad if they don't compromise.
It's true that for this battery for 10$ did last a few months and I might just have been unlucky, and for that price, 4 of these to cover a year is about the same as others I've seen like the Mugen that are over 40$ with a 1 year warranty. But that's a bit silly.
I just wish I could get original ones, at least I'd be more inclined to trust their quality.
So now I await their response.
side note: after a good hour with the original battery back in, I just checked, and while it's at 100%, I see that the temperature is reported at 36 degrees, quite a bit less than the replacement one.