The A series has always been a budget series, but its a damn good deal.
PATA does make a difference, but realistically, not that much unless you think you really need it. PATA is still standard in notebooks nowadays, it'll shift around...
RAM+HD is easy to upgrade and will not void, as long as its replaced back if you ever need to send it back, then its fine.
The CPU and wireless card(depends on model, some do, some dont?) usually have a void sticker.