Absolute beginner begging for advice

[Lynnzer]

Must be boring as you probably get loads of dimwits like me on here asking the same old question.
Never mind, apologies in advance.

I'm scrapping my Sky box as it's just got too damn expensive for me as a new dad. I've seen the Xtrend ET9500 Enigma 2 twin satellite tuner ads and would like to see if I have things right in my head before I make a purchase.

First off, my router is upstairs and the box will be in my living room downstairs.

1. Does the box have wifi and is it good. See question 6. Might be the answer to this.
2. Would I need an ethernet connection to get best speed.
3. Could I use the hard drive from my Sky box in the 9500
4. On the order page it gives options I don't understand. Is the Factory Default firmware good enough or is any other other options better/reliable
5. What's the USB storage and is it necessary for general programme saving if a hard drive is installed.
6. USB Wifi option. I take it that this is the answer to my 1st question. Is the speed of the 150MBPS good enough for most applications or is it limited. If so why?
7. What are the network powerline homeplugs? I think that they may be the things you plug into an electrical socket for use of the broadband through the home electricity system. Am I correct?

Please don't go on about other boxes as I can't get my head around this. I'm not as experienced or knowledgeable as the forum members so really just want quick answers for the above so I can order the right choice.

Oh, is there any fibre optic deal somewhere that offers just the line rental for broadband access I don't use a phone at home as I have my i-phone.