Re: extractor 4-1 and 4-2-1
4-2-1 are more intended for low revs and mid range. This helps during city driving or when u need just the right kick to overtake.
4-1 are designed for higher rpm range. I don't think this is appropriate as you don't usually rev ur engine that high most of the time.
Anyway, I don't think it is wise to change the extractor. A wrong design custom extractor will cause lots of problem to you such as loss of power. It is vital that an extractor measured and bent properly. If you still insist on changing, I would recommend hot bits extractor as I previously had on my satria and it was good.