Would I notice a difference compared to the stock exhaust during cruising and light acceleration?


G8 GXP M6

Yes there would be a difference. It will be noticable. The corners of your lips will curl upwards.

The HFC's are what add ~15% additional sound.

Just the mach balanced, it will be 'quiet' at highway speeds, but during acceleration and city driving, you'll definitely notice that "its not stock".

Why not stop by here (http://www.g8board.com/forums/showthread.php?t=28694) and see if you can arrange to ride along with a local-to-you solo customer who has it installed. Then you can get a real-world feel for what it'll sound like and feel like, if you decide to get it on your car.

do NOT depend on youtube videos, they do not do any exhaust system justice!

Good luck!

Thanks for the feedback.

I am looking for more sound but only under load. I like the stock quietness when cruising or slow accel.



The HFC's are what add ~15% additional sound.

Just the mach balanced, it will be 'quiet' at highway speeds, but during acceleration and city driving, you'll definitely notice that "its not stock".

Why not stop by here (http://www.g8board.com/forums/showthread.php?t=28694) and see if you can arrange to ride along with a local-to-you solo customer who has it installed. Then you can get a real-world feel for what it'll sound like and feel like, if you decide to get it on your car.

do NOT depend on youtube videos, they do not do any exhaust system justice!

Good luck!

Then you will probably be better off with a catback WITHOUT aftermarket cats (http://www.g8board.com/forums/showthread.php?t=29499).

Too much sound for you with aftermarket cats. Look into v2+J. (http://www.g8board.com/forums/showthread.php?t=28454) Drone free and the quietest that they offer, without cats.

Or try the washer mod, lol :drool:

I guess I will have to live with the sound as I want the performance of the HFC. Just want to find a muffler set up with a good balance of performance/quality and quiet.

Sir you are looking for HFcats by themselves. Delete the pup cats if you got them. Leave the rest stock. That is what I have done to my GT. I wish I had the GXP mufflers. To get the added sound that you will already have.

Sir you are looking for HFcats by themselves. Delete the pup cats if you got them. Leave the rest stock. That is what I have done to my GT. I wish I had the GXP mufflers. To get the added sound that you will already have.

Has this been done and did it cause any CELs on stock tune? I'd like to do this but don't want to do a tune, yet...

Has this been done and did it cause any CELs on stock tune? I'd like to do this but don't want to do a tune, yet...


I don't think those cats are monitored by o2 sensors, only the upstream ones.

I don't think those cats are monitored by o2 sensors, only the upstream ones.

Correct, I'm referring to the cats at the manifold, not pup cats. I have an '09, not 09.5.

Correct, I'm referring to the cats at the manifold, not pup cats. I have an '09, not 09.5.

I have the 09 (not 09.5) and I have the pup cats. There must be some builds that got the exhaust change before the bluetooth was introduced.

I'm also looking for a way to get the performance gains without making it too loud, but then who am I kidding? I am putting Kooks 1 7/8 mid-length catted headers on, but am waiting to get enough pocket change to order the Mach-Balanced. I wan to put them on with a tune at one time.