Dell inspiron 1545 vs inspiron 1440 ( Pick the best )

Hi guys after a great research i concluded to post my query here as i found this site hsa more techie issues discussed.So now am planning to buy a laptop.After narrowing i landed with Dell inspiron 1545 or inspiron 1440.
After long research on differnt websites i had these doubts.

Ok now my query is the 1545(model : S541018IN8) & 1440 (S541003IN8) : Almost has a very similar sonfig but i just wanna few techie stuff cleared here( All my questions are relating to the configuration given in the dell website for india and the 1440 is 1000 INR bugs cheap ).

1.Eventhough they have give the RAM are same for both, they have added 1545 has NECC SDRAM. So it means its a negative for it. Rt? and if someone has 1440 tell me the upgradable range for it (eg: Till 4GB or 8GB ).

2.Display
1440 : 14.0 " High Definition (1366x768) LED Display with TrueLife(TM)
14.0" High Definition (720p) 1366 x 768 WLED Display with TrueLifeTM
1545 : 15.6" 720p WLED (1366x768) Display with TrueLife(TM)
So now again it means 1545 is not HD. Rt?

But guys i went to dell showroom and checked a thing in the windows logon screens on both ..1545 has a pleasant view but 1440 has a brighter rough view.i dnt knw whether it has to be adjusted or its basically like that.i tried to adjust the brightness but no help.Plz comment on this too.

3.one more thing the store guy told me is that in 1440 an ATI graphics card (only ATI but not nvidia ) can be added in future if reqd but not in 1545.is this true ?

4.1440 is lighter too in weight and compact to carry places than 1545.

So anyway..my opnion now is slowly changing from 1545 to 1440 but still i need some expert or experienced advice on this..thats y am here.

Sorry writing more but jus wanna make things clear to u ppl. if possible even email me in [email protected] . Thank you all in advance.
Take care guys.