I want to upgrade the stock muffler on my newly acquired 06 C4S, and I am looking at Agency Power ($950). That seems to be a very good price. Too good? Has anyone installed one? Any feedback are really appreciated. I listened to a couple sound clips and it does sound good but is there any drone at highway speed 75-85 mpg...?
Any used one for sale?
Another option would be the FD Fister partial bypass or the Fabspeed bypass..
Any advice?

Thanks

 

I have Fabspeed sport cats and muffler and am very happy with sound and quality. I bought a "cheaper" option at first and of course it wasn't good quality and sounded like a chainsaw. You get what you pay for....

 

I recently bought the Fister mods. Darren Fister was very accommodating. He said to keep my stock mufflers for a week, and if I didn't like his modified mufflers I could dismount them and send them back for a full refund. Of course, as he knew I would, after a week I sent him my stock mufflers and kept his. No drone whatsoever (and I have a cabrio), but when you get on it they wail. For less than $300, Fisters are one of the great mod bargains out there.

 

+1 on Darin

 

Thank you for the insight but out of curiosity, was your bad experience with the Fister or with the Agency Power mufflers?

 

That is quite an endorsement I definitively will call Darren. Did you remove and install the mufflers yourself or did you have a shop do it for you? I am a little nervous at the idea of removing the rear bumper and lights to gain better access to the mufflers. I wish I could find a DYI video or manual to show me the way.
Thank you for the post, that was very helpful.

Cheers,

 

I agree, go with the fister mufflers, I personally changed mine myself , about 30 minutes per side, three bolts to remove the muffler, A couple more bolts here and there, you do not have to remove the rear bumper as some people and or sites will suggest, it helps if you can lift the car a bit.

 

I use an independent Porsche service facility in Pasadena, House Automotive, for all my service needs. Excellent service, good people and fair prices. I had Darren ship the mufflers directly to them. I watched as the tech took off the old mufflers and put on the new ones. No bumper removal, no wheel removal. About 20 minutes per side, more or less. The hardest part was lining up the exhaust tips precisely after the new mufflers were installed.

I had Darren enclose a prepaid return label with the mufflers. House put the stock mufflers in the carton the Fisters came in, and when I called them after a week and told them to send back the stock mufflers, they just slapped on the prepaid label, sealed up the carton and gave it to the UPS guy.

I'm an old guy, and decades of flying 4-engine turbo-prop aircraft has left me with a low tolerance for noise. The Fisters, for me, give the car just the right amount of "voice" without shouting "Look at me". But don't take my word for it; check out the online reviews. And best of luck!

 

I copied this from a different forum but it's almost the same steps I took in order to replace the mufflers, no wheel removal no bumper removal, very simple...

if you have jack stands i would raise both rears on stands... wheels can remain ON.


WAIT TILL CAR IS COLD, EXHAUST BITS GET HOT!

first steps are to loosen all hardware:

1: loosen and remove the 3 bolts that connect the CATS to the OEM center muffler (i believe 12mm or 14mm) (top one is difficult, but their is a bracket on that bolt that holds on the side cans)

2: loosen the 2 bolts on each of the 2 "clamps" that connect the center muffler to the side cans (these dont come off, just loosen until you can slide the "clamps"either onto the center muffler or onto the side can piping) (same 12 or 14mm)

3: loosen and remove the 2 bolts per side that hold the side cans onto the car (they are right by wheel well same size as rest (sorry i cant remember if 12 or 14mm)

4: remove the metal bar that connects the rear bumper to the car, one side is a ALLEN bolt the other end is a 10mm bolt

5: loosen bolt on exhaust tip, and pull exhaust tip off car (both sides)

NOW YOU WILL HAVE ALL EXHAUST STILL ON CAR BUT ALL NUTS REMOVED SO EVERYTHING IS JUST HANGING FREELY AND NOT CONNECTED

6: remove the side cans first (slide off the side bracket, and then weight will be on the other bracket by the cats)... it will then slide down when released of the bolts and u can angle it inward if needed to have it slide down... with the side bar removed as you did on step 4 it should slide out.. maybe pull slightly to have it fall out)

7: repeat on opposite side

8: remove bracket on oem and install on cans i sent you

9: remove the center muffler, two braces go around the muffler and are held on by allen bolt, remove bolt completely.. slide braces to the side and muffler pulls off. (do not reuse these braces on aftermarket center)

10: take the clamps that held the oem center muffler to the oem side cans, place these on the aftermarket center pipe on the correct sides..

11: install aftermarket center pipe, the cats slightly "sag" when you remove the oem center pipe so you might have to use a pipe or something to pull/push the cats slightly to line up the holes... i have "widened" the holes in the aftermarket center pipe to make this work easier, you can do the same if needed. ***note, please reuse the oem "washer" that goes between cat exit and center pipe (its triangle flat piece of metal)

12: put inner most bottom nuts on (at cat) to hold on temporarily, loosely just so center doesnt fall off on your head)

13: put on new side cans, sometimes tough to slip up into hole but its not bad... just angle em in a lil and slide up.. put can on bracket by the wheel well... then that holds it why you get the bracket that slips on the bolts by the cat...

14: put nuts on the side bracket, put nuts on the CAT bolts, slide clamps from center pipe over halfway between side cans and center pipe..

EVERYTHING WILL NOW BE IN PLACE BUT NOT TIGHTENED.

all exhaust nuts get tightened to ONLY 15 ft/lbs (this is pretty much just past hand tight, a little play is required on all exhaust bolts as if you tighten them too much it will cause a vibration in the car at idle, if you notice a vibration at idle, check these nuts...

15: replace the tips, these might take a little work as they need to be "spread" out slightly to slip back over the pipes... i kinda tapped them with a small hammer and spread the clamps a little so they would slip over the pipes on the car.. tighten this bolt (i always did it very snug as to not lose the tips off the car whilst driving)

 

By the way this also includes the cat replacement with x pipe, so skip that part....

 

if you're worried about droning, then stay the hell away from the Fabspeed bypass!!!!

 

Just installed and test drove agency power on 09 c2s
It's decent
Tubi would have sounded more like I wanted but 2000 more. That's not worth it to me
Would like more raspy sound
Maybe it will burn in some as I drove it
Install is easy and fitment is good

 

Thanks for the detailed DYI, but I did it the hard way, I decided to remove the bumper, lights and wheels to see what is going on underneath. I took my time and cleaned everything. I installed the Exhaust with the Fister mod that Darin sent me and I love the result. I drove the car on the freeway at speed and there was absolutely no drone and the sound was very subdued. Starting the engine gave a nice growl and going through the gears the exhaust note was louder but not obnoxious. I would definitively recommend Fister to anyone who want a nicer sound without having to spend thousands of $$$$$....

 

where can I order fister exhaust?

 

Call Darin.... (925) 765-5703

FD Motorsports. He is in Brentwood, CA