Metronet

I marked them with long, straight lines (in 3 dimension) before I cut off the badly rusted flex joints (or whatever was left). It can be a little bit off, with the flex joint the main cats have a little room to move around but the overall length of the downpipes can't be too short or too long in order to connect back to the cat-back system.

I decided to have them welded off-the-car instead of going to the exhaust shop (they do it in-car here). The reason was: I wanted to remove the pre-cats to make piggie pipes. While I had the catalytic converter separated I also attempted to "re-activate" the catalyst with Oxalic and Citric Acid. I'm not sure how successful it was but a lot of dirty stuff came out. See attached PDF if you're interested to read on. Good luck!

tester123

That makes sense. What was your total cost? Although I could do this, I don't have access to lift so, I checked out another exhaust specific shop and he quoted $165 per side including the flex pipe (which is not the main cost anyway). I am thinking if $300 for both sides, it might be worth it...?

SloopJohnB@mac.com

The flex pipes went on my 02S6 and Audi just replaced the entire cat pipe. One was under the 10/100 warranty (went at around 90K miles, inside 10 years), the other one I just replaced the entire cat pipe to keep the thing OEM.

Metronet

The total cost for me was around $300 (Canadian) also. And for $165 per side I think it's reasonable. If they do it on car it's easier to guarantee the fitments.

I'm not sure about the 4.2 C5s but for the 2.7T you just need fronts to be on ramps, no need to remove the cat-backs. You slide off the sleeves and the Cats section will drop off.

If I had an S6 I would definitely go with the OEM route or Megnaflow direct replacements. Working on the exhaust is just too much work for me!

16vcabman

took mine to a local muffler shop. They cut them out and replaced them for 200.00 I thought that was a deal.

jcman

$200 for both, that's one heck of a deal.

16vcabman

Yea the guy is in Clarkston Michigan. When I brought it in he said 300 then I told him guy in Pontiac quoted 200. He said he would do it for 200. Said he just had finished one the week before so I knew he knew what he was in for!

jcman

Any chance the guy is Mike Hunter from Clarkston? Old times and old friend from my Michigan days before the current Ohio venture.

tester123

UPDATE:

Finally, decided that this is something I do not want to handle (mainly due to lack of a lift and welding tools), I got it done at a local shop and they set me back $325. Got both replaced to avoid further visits.

Perhaps a bit more than I was hoping for but it is done and the car doesn't sound like a expensive lawn mower.

Thanks for everyone's input!

16vcabman

Not Sure, I did notice the place is closed again!