Sloopy

Looking for the best exhaust for me lasted some time, so here is my input after a long search and picking up the car yesterday after the install; just short of 10K miles.

I have listened to all the videos but could never tell that much from the sound transfer. My take is you have to hear these in person before you decide.... No video was going to prepare me for when I heard my car for the first time.

My decision was based more on design and knowledge of sound.

Fist: I waned the valves to be active as I wanted sound to be quieter in cruise and louder when playing in the mountains. Since I use the car for multiple purposes and most all on the road I also wanted no loss of torque in lower RPM.

Second: I felt that my GT3 could use a little lower tone so GMG's bypass with lager pipes would produce lower tone than say a Sharkwerks. I was also concerned with loudness and felt the GMG would be louder. I also know that splitting the cylinders side to side would make a difference in sound. Left and right side sounds different when the exhaust is combined so all six have similar exit. GMB has a pass through from left and right side exit so the sound will be different than without. Sharkwerks does not, but it may make up for the tone from different sized pipes.

Third: I liked the idea of equal length headers as power per cylinder is more matched when intake and exhaust length is equals for each cylinder. I realize that Porsche does an excellent job and may not even show on a dyno but I it should be there though small. Beyond the tone, the headers and 200 cell cats offer some advantage in performance across the entire rev range where the rest is just sound. I also like the idea of no tune or lights. I did check with my dealer and they have no issues with any of these changes; In fact they did the install.

Forth: I was afraid that GMG alone may be a bit less aggressive than what I was looking for so I felt the addition of headers with 200 cell cats and bypass wad more to my liking.

The results: Start up and throttle blip with sport button on is insane. Sales person drove it out of garage for delivery and several people were standing in awe with huge grins. There is no way I was prepared for this sort of loud.

On the road with windows up there is very little increase in sound at 60 to 80 range. Before I could pull both paddles at 60 and sound would be no different due to road noise. With the system installed you can just barely hear the engine go to lower RPM. It becomes more noticeable up to 80 but very smooth and no drown can be detected by me. (I do ware hearing aids).

I drive mostly in manual with sport button on and can very much hear the system and it really lights up when the values open.

In closing I always felt that the cars characteristics were like watching a action movie with the sound muted. Now the sound now seems to better match the car. Still very livable below 3K with the valves closed and good for long distance and a monster when the valves open and the RPM rises.

CDinSing

Thanks for the update Sloopy. I share the same disappointment in the stock sound. I had a 991 S with sport exhaust and loved the sound, so felt the GT3 needed a boost. I have mine on order. Can't wait for the install.

0to60

I have the GMG oval in black and really like the sound and looks.

gmgracing

Happy to hear you are enjoying your headers and center section John!

991 GT3

Ive got a GMG center on the way. Excited to get it on!!! Is it a big difference from stock at low RPMs like a growl and with pse on at lower RPMs does it make that big of a difference. I know at high RPMs to expect intensity, which i love

reidry

We went to the mountains with close to 40 other GT3s, at the time our car was still stock. Stock is ok, but certainly not what I wanted. I was heavily leaning towards the Sharkwerks, even bought a second hand one.

My wife gave me the "you should have bought the GMG"! Before I installed the sharky, I listened to Money's detail videos over and over on the GMG and changed my mind.

The GMG is aggressive, just what I wanted. Only downside is the GMG doesn't pass sound at some tracks and you need to wire the valves shut.

Ryan

James-GMG

Now that's a cool wife! :-)
Seriously, thanks for all the support guys and John, thanks for the write up and we are all happy at GMG that you are enjoying your exhaust system.

Cheers!

Sloopy

I drove it again yesterday & it really fits the bill. Glad I also got the headers. Took my assistant to lunch and she says it feels like a rollercoster.

sgroer

Who could ever forget that weekend! And just think, we're doing it again in < 4 months! Bigger and better! (James - you should ship your car here :-) )

reidry

I'll second that!

Ryan