Ok, I have a 1999 Civic Si with Greddy EVo catback. THe catback was off of a 4-door civic, so it bolted up to my car...all I had to do was remove my catilitic (sp?) converter.

I know the DC Sports JDM 4-1 header will bolt up on the primary side, but the flange supposedly needs modification to work properly.

My question is has anyone done this, is it hard to do, should I explore other options or what? The reason I chose this header was good price and seemingly one of the biggest power creators.

Please help with ideas and suggestions. Thanks!