greeting sifus,

I'm driving a stock 4g13 year 02(siemens) and seeking some performance gain with minimal cost.

1-my ori extractor should be 4-1 if i'm not mistaken, and now i'm really confuse .. some people told me not to change the ori extractor to 4-2-1 as the stock extractor provide more low end power. Anyone can clear my doubt?

2-My other question is .. can i use back the ori piping and muffler if i wunna use 4-2-1 extractor?

3-Does changing the 4-2-1 increase FC ?

4-I heard that zenden 4-2-1 were quite good, does anyone really feel the performance increase using buttdyno?

thanks