My car is not built but I wanted just some more sound out of it. Read so much about exhaust on here and determined a good setup with zero drone is the GXP axlebacks, with the GT midpipe modified to eliminate the mid-muffler and resonators replaced with X-pipe.
I waited to find a deal and recently found one, which was axlebacks and the GXP midpipe for one price. Picked up some new gaskets online to get things ready.
I had fun for a few days with the GT AB removed (people stared). It did drone in the 1200rpm range but it wasn't all that bad, however I could foresee that being miserable on long drives.
I put the GXP AB on it (with stock GT mid) for a few days to get rid of the unwanted attention, just used a bead of black RTV as a temporary seal. I could hear a little rumble out of the back of the car but nothing crazy, still shockingly quiet, and could barely hear the 4-8 transition but both modes were quiet with a some popping upon decel;. A little more noticeable idle when standing behind the car, the biggest difference was hearing it with remote start, a noticeable bark at startup.
Update to this week: pulled my car up on my trusty Harbor Freight plastic magnum ramps and made a late night project out of it crawling around underneath, but managed to get it done. Used Mahle gaskets (F32245 donuts in front, F32258 flanges in rear with a fresh bead of Permatex copper on both sides of flange gaskets).
Now running stock manifolds and cats, with GXP midpipe and axlebacks.
More noticeable bark at startup, more noticeable at idle, more noticeable inside at highway speeds, but that's about it. I have not heard it from the outside yet and I have to drive it a little more but initially my impression is - too damn quiet. I'm already preparing to sell these parts and go get a good catback, I've had my eye on the Solo for a while...
Anyone have thoughts on comparing a stock GXP mid/AB setup to an aftermarket catback?
Using Solo's example below, they consider "1-10 scale… 1 being stock quiet and 10 being rockin’ noisy..."
Mach balanced: outside=4, inside=3
Mach: outside=5, inside=3.5
Mach shorty balanced: outside=6, inside=4
Mach shorty: outside=7, inside=4.5
Where does the GXP setup fall on this scale, so I can get a reference? Is it a 2? Or is it a 5? I have no clue.
I used to be thinking I should go with their quietest setup since it seems there are so many complaints on here of the drone/resonance that happens with louder exhausts on these cars, but I have also learned there are a lot of picky people on here (like me!). Now I am thinking if (in my opinion) the GXP mid/AB combo is this quiet (to me), perhaps I should be looking at the Mach shorty balanced...