If you jack up your car, the part where it restrict flows the most is that bend across the cross member or something, from what i heard, its cheap and efficient just changing that part to flexi. As far as I know, you can't really get aftermarket 2-1 section by itself, probably need to get it custom made.
20V headers that increase performance are hard to get. you can get them from japan. if you know some importers you are in luck. FGK is a good brand with proven results for their 4-2-1 headers for the 20V. If you check their japan website, you will find a dyno result of before and after with their headers, but thats only numbers and not the actual dyno plot. Mad dan also makes also headers, I haven't seen them myself, but Bazada get his stuff made by him, and i've seen pics of it, and they are VERY GOOD QUALITY, but i heard he is leaving the country
There are some on trademe, but thats only the 4-2 section, and to be honest, is quite useless if you don't have the 2-1 section to go with it, as the factory 4-2 isn't bad anyway.
