hmm.. pretty easy to check. if the imei number can be register with samsung, then is sme set

Why Not? Extended battery that size is gonna make the note 2 even bulkier and difficult to handle. Having a portable charger is more convenient for some people. And you can use it for charging other phones around you not only your note 2 like your wife/husband/gf/bf/sis/bro/mum/dad/etc. phones. 

At the end of the day it is each user's preference.

+1
When buy ap always ask yourself this questions?

1) will they swap any accessories?
2) will they honour the warranty or put blame on you
3) are their technician well train to handle your phone or you become lab rat?
4) are the parts original? Where they buy the parts from?
5) will they close shop tomorrow?
6) is it worth sacrificing rm100 to rm300 vs original just imagine if anything above happen sme malaysia can choose to reject even u report they can't help you.
7 ) is the phone ap set or water set?  Waterset have lower resell value.
8) is your phone used? Is it stolen? Sometimes box and phone different imei.
9) hidden terms in their warranty like say warranty 5 years but a tiny line in their terms and condition mother board 5 years , phone 1 year,  accessories 1month
If sme original involve

1) if they swap u can make a big a fuss about it to tribunal and news paper samsung malaysia will sure settle for you their dealer might get terminated

2) if they dont honour their warranty can report to samsung via Facebook and twitter or tribunal or newspaper they sure help u settle its their name in stake. Ap they just said the warranty not covered here.

3) high probability their technicians are sent to korea to train compare to ah beng sdn bhd

4) the parts mostly original since they are by Samsung itself

5) will samsung malaysia close down? What u think?

6) anything not happy can report to tribunal or newspaper except you don't break their terms ans condition

7) make sure u check

8) make sure u check

9) all sme warranty are 1 year for phone and 6months for accessories except for extended warranty if available