I have a 2 dr 1.8 SOHC R18A1 2006 civic. Will the si catback fit this car ? Or should I spring for the vibrant? Anbody have experience they could add to this thread? Thanks for your time.

 

I think even the SI catback will be somewhat restrictive. If your truely looking to help free up the exhaust flow, I would think one of the many aftermarket catback systems would be better.

 

The Si catback will not fit on your R18 Civic. If you wanted to use the Si exhaust, you would only be able to use the axle back portion. This really wouldn't give you any kind of performance gains. I would go with the Vibrant if I were you.