oil and upper control arm

[invincibleruler]

I am pretty new to cars and 2002 celica GTS is my first car.
My question might sound silly.
1) What synthetic oil can I use for my car?
2) Does fuel injector really make a difference in increasing the engine's life?
3) There are a couple of scratches on the car. Any idea about the best scratch remover?
4) My car is lowered(the guy before me did that) and I need to raise it up back. The mechanic told me that I need "upper control arm" to fix it. Where can I find that for cheap?
5) From where can I get the manual for 2002 celica gts? I searched a lot but couldn't find anything.