BC996TT

I was told by an independent shop it's about 2600-2700.00 to replace one cat. They said that they have to buy the part from audi which will cost 1300+400 core deposit (they have to give audi back my original cat or they lose the 400.00 deposit). Is this true?

They also said the entire sub-frame has to be dropped/removed, then the car has to be realigned, etc. Seems like a nightmare of a job.

I wanted to do the timing belt as well, but the total repair is going to be over 4K! The car alone is worth like 8K! LOL. I only have 80K on the clock which sucks.

Any less expensive alternative to getting this done?

Mister Bally

Sure, leave the cat. in place. Why do you need to replace it? Is it rattling?

BC996TT

The car sounds like a domestic...... almost as if there's a hole in the exhaust. Dealer said it was the cat. The sound certainly got worse after I picked it up from the dealer.

MP4.2+6.0

+1 And even if rattling, having dealt with this back on my 85 5000, just drill a hole into it and drive in a stainless screw or two.

Besides that, to OP's question, not sure if you have to drop subframe, nor for that matter I guess which cat you mean. On my 2000 A6 4.2, having dropped the exhaust, the answer is definitely not. But I think the D3 started with the newer design that has a pre-cat basically right in there with the exhaust manifold for fast light off, then the main one(s) father back underneath in the "normal" position. Yes, a pre cat in the manifold area would be very difficult. But again, back to basic question: what is the issue and which specific cat?

Also, for an older car like this, why not just get one used from a wrecking yard/EBay? D3's are in some ways fortunately new enough that most of them are in the junkyard due to wrecks (or maybe floods) rather than motor issues, failure to pass smog, etc.

GradecEngineering

I would absolutely get a second opinion. Try an exhaust shop. They may be able to weld the leak.

BC996TT

It's the left cat (bank 1) according to the dealer. However I have no cel so not sure what is going on. I'm definitely going to get a second opinion.

If I can just band aid without going through all the labor etc to replace it, I'm all for it.

However there's definitely a leak somewhere. When off the throttle, it crackle and pops like a straight pipe set up...but the sound is certainly coming from the front of the car.

2001 S8

Doing a quick search, I found three options if you want to fix it instead of doing a band-aid.

MagnaFlow - $540.73
RockAuto - $174.95
Car-Parts.com - Salvage Yard search site

Good luck.