Street Friendly (And California Legal) GD Subaru STI Build! Part Three, Getting Some Green Power With Cobb Tuning

All the flanges are stamped and formed for stiffness and light weight.

A lot of expensive lightweight exhausts have this same feature.  We are very impressed with the latest exhaust offerings from Cobb!

Now it is time to install the Cobb exhaust. The stock exhaust is small in diameter and has some tightly crimped flow reducing bends.

Jason is looking at how much the stock exhaust tip protrudes from the bumper so he will have an idea of where to set the Cobb tip at.  To start the removal, the stock exhaust is supported.

The stock exhaust is unbolted behind the factory cat which of course will stay in place.

The exhaust hangers are removed which will allow the stock exhaust to be removed.


  1. I know there was a lot of complaining when Cobb decided to pull a lot of their parts recently, but I’m excited to see what they can do while still being CARB compliant, especially with Flex Fuel and down pipes. Hopefully this owner decides to do more if/when the Project Green Speed development is fully fleshed out so the readers can get a no BS article about what is and isn’t possible while following the rules. As dumb as they sometimes may be…

  2. Thank you for the great article. Do you have any recommendations for an aftermarket turbo intake duct? There are a number of options on the market. I’d love to know what your experience has been with them, which is your favorite, and why.

    It looks like the resonator chamber had already been removed from the fender. Cutting out the back of the air intake duct, as mentioned on page 9, seems like a good idea, especially if the resonator is gone. But, wouldn’t you also recommend blocking off the two giant holes in the inner fender wall which, without the resonator in place, expose the air cleaner to all the road grime blowing past the fender liner?

    Thanks again for the excellent content!

  3. I see you used the COBB titanium cat back, is this similar to the older COBB catbacks that neck down to 2.5′ at the area that mates to the downpipe, or would this be a true 3′ all the way through?

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