I can't believe how many useless one-sentence replies there are in this thread. Horrendous.

There is ABSOLUTELY NO POINT in running a header with a 2.5" collector unless the rest of the exhaust after the header is also 2.5" in diameter.

The DC JDM 4-1 is good for not too heavily modded cars but once you get up there in the output you really need something better.

The Kami is good on JRSC cars even though it's trashy. With a little creativity you can get it to fit nicely.