http://breakfixnow.com.sg/smartphones/
i smsed them on changing battery and got quoted $50
Personally, I bought this replacement battery off eBay. Haven't run into any issues so far. Battery life is the same as an unexpended original battery. It's not difficult to replace. You only need something like a guitar pick or knife to pry the back cover and have a small phillip screwdriver.
http://www.ebay.com/itm/251718980057?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
The only difference I noticed was this:
-Feels more dense than the original battery, slightly.No problem fitting it.
-When unpacked, LG logo was doodled off with permanent marker (can use alcohol to erase)
-Battery part no. etc stamped on the silver side indicates its a TSDI, could be reference to Samsung TSDI, possibly Samsung cells.
-When using CPUID, u can see that the voltage range is 3.5 (esp when low bat)-4.2mV. Whereas the original was stuck at 4.1mV.
Overall, I did put the phone through deep discharge cycles to 0 batt (unintended) and it hasn't failed at all (still completely operational) as opposed to some imitation batteries that completely die out if you do this. Common sense battery care still applies, try not to do deep discharge cycles or let it charge overnight.
I did hit low 3Hrs of SOT on 0-50 brightness so far with 3G always on with Android M already.