No it won't effect your N line, the guides on here are for the "openvix" image
as that is generally the most popular, even the Zgemma crowd want it lol
So for anyone who is not familiar order a box pre-flashed with openvix if you want a guide to follow.
If you are familiar with what is required to set up any E2 type box then the image isn't that important, the menus
will just look different and there isn't any other guides about at the moment.
As for Hdd's as cactikid said, don't go too big, they are used for recording, if you don't record you won't need one.
The Hdd can also store the EPG.
If you only want to store the EPG a USB stick will do.
There is a guide
here
and a request thread for lines,
here
Important :Read post 1 before requesting
Also just to clarify E2 boxes can take a variety of "images" this is the equivalent of firmware.
The difference being firmware is usually written for a specific box by the box manufacture.