I'm newbie

, What do you recommend to me?

is it recommended to install jailbreak?
1. will it affect performance and speed of kindle?
2. What is the exact procedure for installation? (
https://www.mobileread.com/forums/sho...d.php?t=227532 ?? this is?) Please give detailed recommendation. My Device is "Kindle Whitepaper 2nd Generation"?
3. Could I upgrade firmware to newer version later?
4. Is it possible to install original/default firmware again?
5. will it be possible to open epub files also?
6. First upgared then jailbreak or otherwise?
7. Could I register on amazon after jailbreak?