Advice needed: x4d or x3c?

Hey all,
I've been looking for a laptop for quite a while now and after following this useful forum and ruling out the MBA and the XPS 14 i've decided to go for the SS9 as my new laptop. Only thing is i've been wondering whether i should get the x4c or the x3c.
The thing is that the only models availabe in my area are:
1. X4d 4gb i5 128gb ssd
2. X3c 4gb i5 128gb ssd
3. X3c 4gb i7 256gb ssd

I will use it mainly for work (some ms office, some heavy browsing and some not-so-demanding financial software) and secondly as a media center (some downloading and playing 1080p movies, shows etc.. through WiDi).

Screen size is not a big issue as it'll be hooked up to a seperate display most of the time but it sure is useful to have seperate PgDnUp, Home,End buttons!(as it is on the x4d).

My main concern is if i get the maxed x3c i won't be able to upgrade the ram in the future(do i even need 8gb?) and if i get the x4c i'm stuck with the i5 (is the i7 that much better or necessary?) What do you think is my best option? Getting the i7 x3c 256gb or getting the i5 x4c along with a seperate 256gb ssd knowing that i have the option to upgrade to 8gb of ram in the future?
What is more future proof? i7+4gb or i5+8gb?
(Cost is not an issue as it is a gift)

P.S: The x4c i7 is not an optipn as it will not be available anytime soon in Israel.

I hope i made myself clear enough and thanks in advance for your advice!

 

I gave my answer here to your very similar question in another thread.

John