I have the newer perrin dp without cat. They don't make it with a cat anymore. Quality is great. Fit great @ the turbo. I'm just having trouble getting it to work with my 3" Stromung Cat-back.

 

lowball, what trouble are you having getting it to work with your 3" Stromung Cat-back? is it the stock donut gasket?. I have my Perrin catless DP ready to install going to mate it up with my 3" Cobb CB. Afirm on the Perrin Quality.

 

I think it's just a Perrin/Stromung thing. For some reason on my car they arn't matching up at the connection point and I have an exhaust leak at the flange.

Not sure if it's that the rear exhaust pipe from Stromung is to long or if the Perrin and/or Stromung flange is off just a bit. At any rate, the Perrin DP is much better quality, especially at the flange then the Stromung cat back. The Stomung cat-back flange is more like a stock flange, where as the Perrin is much larger and better in quaility and much better welds. My Stromung axle back pipe is hitting my rear diff. (one of the bolts) and some sheet metal part of the car. Stromung said it must be Perrins DP causing the problem and Perrin said it's the flange on the Stromung CB.

So at this point I'm taking it to another exhaust shop to see what they can do. If they can't fix it I'll sell the CB and get the Perrin one @ $700 more dollars

As far as the gaskets. I've tried three things. 1) the stock donut gasket install in reverse. 2) the stock donut gasket and a 3" two bolt gasket. 3) a double sided donut gasket (from the exhaust shop). None of these things stopped the leak.

The Perrin DP may work fine with the Cobb CB. You'll have to try it.

 

i have the perrin downpipe just like you lowball and the 3" stromung cat back i had a little trouble putting it on but got it on only problem with the three inch pipping it touches the rear diff a little so i have to do something about that other than that its ok.

 

I have the older Perrin catted DP with the 3" Stromung mid and axle back.
I had similar leak/fitment problems.

The DP-mid leak was fixed by making a 'shim' out of a piece of pipe which fit inside the DP which pushed the 'donut' gasket further back toward the mid pipe flange. The 'donut' was being pushed too far into the DP and the seal was NFG. This 'shim' piece was ~1/2" of pipe the same dia. as the donut, just pushed(tapped in with a hammer) into the DP, and then the 'donut'.
I have no leaks for ~10k miles now.
The fitment problem, which is either the DP is too long or the mid-pipe is too long(or both???), which pushes the axle back too far back.
We cut the axle back pipe about 14"(IIRC) from the mid-pipe mounting flange and expanded the pipe a bit, slid one piece over the other until everything fit as well as it ever was gonna fit and welded it.
I fabbed a silicone 'hockey puck'(I used a greased IC-TB hose...lol) with plain clear silicone caulk to put between the mid-pipe and drive shaft loop to prevent banging there, and done.
Great sound and real nice power.

 

Man! That sounds like it would work for my problem too. Wish you had some photos of that. I think the Stromung 3" set up is to long IMHO. It seems like my axle back section is just not right. Like the exhaust hanger on the left side of the car is to long and it pushes the muffler and the piping over toward the direction of the rear diff.

 

Yeah...Something is DEFINITELY too long in this combo, and the tip off is the 3 back box hangers being stretched(not the mid-pipe one though), and the back box can touching the upper aft most area behind the bumper.
I have to take some pix, anyway, of my battery install(I put a PC680 under the passengers seat ).
What do you want me to try an get a pic of?
The solution was to cut the piping just behind the rear diff, and use the pipe expander at the muffler shop to open up one piece so it slid over the other piece, shortening the fore-aft length ~2 " overall...once you cut the pipe, the whole assembly 'relaxes' and takes its own 'set'. That is why, I think, I had contact at the drive shaft loop, too, because once the tension was released, it hit the loop.
<"My Stromung axle back pipe is hitting my rear diff. (one of the bolts) and some sheet metal part of the car.">
This is/was exactly my problem, too.
IMHO, somebody's(Stromung's, I'm sure) jig is tweaked a bit, causing problems down the line. We should get a Stromung guy to read this thread and tell us that it's the Perrin DP causing the problem....I DON'T THINK SO.
My 2¢


My apologies to GM6 for hijacking his thread, maybe this should have been a separate post.

 

Since you have had them both can you explain why you like the Invida better?