#1
Okay, I have decided to buy the Peavey Valveking 112 with all of those threads about it (lol) and I read that you need to change the speaker and tubes and can somebody recommend a good speaker that can play all sorts of things and some tubes that can play all sorts of things? Could also someone link a video or a guide on how to change these things too? Thanks.
#2
For the tubes and speaker go here

http://ultimate-guitar-valveking.wikispaces.com/

or here

https://www.ultimate-guitar.com/forum/showthread.php?t=969296

As for videos about installing tubes and speakers I can't help you out with those. There's lots of useful information at both those sites (they're roughly the same thing).
#4
What style of music do you plan on using it for?? This will make a difference as to which speaker you will want.