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[Matt0987]

I believe that if you get the exhaust first you will free up the breathing of the engine. Lower egts. And make the tuner perform better when you get around to it. If you install the tuner first it will be limited by the back pressure from the stock exhaust.

When I was doing mine, see my sig for what I have done, I read from the manufacturer that there was a horse power range recomendation for the 4" and 5" exhaust. Based on their, MBRP, recommendation I went with the 4" exhaust. I never plan on having 450 hp or more generated by my engine.

Their system also has a nice sound to it. Stainless, of course.

They also have, and I do not recall if they did when I got mine, a nice "Laker" type set up where the system splits into two and comes out in front of the rear tires.

But I would, and did, go with the exhaust, then the tuner.

If you read the forums regarding the air intake on this site you will find recommendations to save your money unless you are looking to just dress up the looks of things under your hood. For in depth arguments for this recommendation I would suggest that you search for those forums.