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

The exhaust is now ready to roll.  Boy does it look nice.

The tip does not stick out too far but is still visible and looks nice.

Next was the Cobb SF intake.  This is a high-flow short ram intake with cold air when used with the optional air box.

The SF intake can be installed with the SF cold air box.  We really recommend this option as cold air is basically free hp with no downsides.  The airbox shields the intake from ingesting hot underhood air.

The SF intake uses a washable and reusable dry element filter that does not need to be oiled.

The intake uses this larger MAF housing with a built-in velocity stack. It is recommended to get one of Cobb’s OTS (Off the Shelf) tunes when using this intake due to the changes it can make in the MAF readings.


  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?

Leave a Reply

Your email address will not be published. Required fields are marked *