# What Exhaust system is best?



## Jamie2525 (Aug 22, 2011)

Alright folks I need some opinions.... I have a 05 GTO...CNC Port and Polished heads...Comp Cam .619/.624...239...113LSA....Pacesetter LT Headers with Pacestter midpipes (No cats)...I still have the factory resonator and Flowmaster Mufflers...My last Dyno was 435/418. I want to get rid of the factory resonator and my motor guy makes fun of me for the Flowmasters..He says they are just way behind the times in performance. I am kinda leaning toward the SLP Loudmouth catback kit but have heard some say that Magnaflow is good. My car hits a good hard solid beat but I think I can get more RWHP from an engineered system instead of my local muffler shop weld on FM's...I have also read that taking out the resonator creates more "exhaust popping" shifting between gears....Any and all opinions appreciated.


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## 87GN06GTO07IRL (Aug 10, 2009)

Not much is to gained swapping out catbacks on these cars. Save your money and spend it elsewhere.


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## jpalamar (Jul 22, 2008)

If you want more HP... get Kooks headers. As much as they are it is a better investment then a catback. Aftermarket catbacks don't do much/if anything for HP. They just sound cool and probally weight less(atleast my JBA did).


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## BWinc (Sep 21, 2005)

If you want a new sound, get a catback. If you want performance, I'd make your next mod 3.91 gears.


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## LS2 MN6 (Jul 14, 2010)

Catbacks are more for acoustics than anything else (I have catback systems on each of my cars solely for acoustics). If you are looking for more flow you need to look further up at headers and high flow cats.


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## dustyminpin (Jun 19, 2006)

A good aftermarket catback will net you around 5 HPish, at least that's what Borla claimed on dyno tests of my exhaust. It's the sound, the quality of stainless steel, the looks of the tips, and the weight reduction that you're after. I liked the 5" tips of the Borla and already knew what they sounded like on my buddy's '99 Lingenfelter Vette so I went with them. They are a little over 20 pounds lighter then the stock oil drums that come on the car.


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## Ali_mkm (Mar 6, 2012)

i think the magnaflow 3'' is the beast


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## Angiej (Sep 22, 2011)

Corsa Sport catback , wont find a nicer exhaust


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## Gotagoat (Jan 6, 2006)

Skip shift and Kooks Afterburners are the only two mods on my 05 M6. Acoustics were all I wanted and I have really enjoyed the sound and quality of the Afterburners. Can't count the number of compliments I've received from guys at parking lots, stop lights, garages, etc.


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## svede1212 (Nov 1, 2005)

Put on LTs and you get the same compliments and 25 RWHP


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## psycho1000r (Dec 14, 2007)

kooks stepped headers, cammed, ported heads and bassani cat back
i recommend bassani, not to loud, not too quiet, just right for me.

i made 475/408


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## Rob GTO (Apr 28, 2010)

Angiej said:


> Corsa Sport catback , wont find a nicer exhaust


I agree, if you want it a little more tame, go for the Corsa Touring.


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## Gotagoat (Jan 6, 2006)

svede1212 said:


> Put on LTs and you get the same compliments and 25 RWHP


Given a dependable shop in my town, I'd do that, install a GMM shifter, and one of your CAIs. Lacking any, I've remained pretty much stock.


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## Jamie2525 (Aug 22, 2011)

I already had Pacesetter LT Headers and catless mids..I still had the stock resonator and a set of Flowmaster 44'S welded in place of the stock muffers. I recently swapped the resonator for an X Pipe Spintech system and HOLY MOTHER OF JESUS its loud!!!


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## frtaylor9 (Mar 19, 2012)

I just have bolts ons, without any internal work yet...but for now its not to bad, I think this setup would sound beast with a cam....Although I do like the bassani from _psycho_

SW LT's & HF Cats X-pipe into 3'' Flowmaster outlaws, that have been DEI Silicone heat painted & cured.


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## x47544F (Apr 11, 2012)

Kooks SS 1-3/4" -> 1-7/8" w/Jet hot sterling silver 

(They are super nice looking) I might post a picture...

+[3"<->3"] cats. One day I might go catless...
+Kooks street screamer catback

The machining was well done. All the welds were good. It isn't in the car yet though. 

Btw, total shipping weight was 125 lbs. if anyone is interested.


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## bondpw01 (Jul 2, 2012)

I just put the Kook's streat screamers on my GTO. It sounds amazing.


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