Plastic Modelling questions (priming etc)

[naglaro00]

So...
I've been wanting to buy an HGUC Sinanju and I don't like red. Nein.
If I do get that sinanju...
I plan to color it black, white and silver. (or maybe something else, but NOT red)
But nevermind the details.

QUESTION 1
Do I REALLY need primers?
QUESTION 2
Do I have to sand after priming?
QUESTION 3
Does Future Floor yellow in time?

 

[glowy]

Q1
depends on the material
Q2
definately, unless you want paint chipping off over time
Q3
dunno