What is needed in a 1.8t exhaust.

[Turbwhistle]

Well i have been looking into this for some time and i have went to get my exhaust welded up and the past 3 shops i have went to have said you need a cat/catalytic converter, i have my stock cat but i also have a 2.5" test pipe. I told both shops to put the stock cat on and weld up the exhaust the way i wanted which will be posted below. They continued to tell me that they can not do it because 1) they can make the flange that goes to the cat/tp, and 2)my flex pipe is ruined and i need one. So, this is where the questions begin. Do you need* a flex pipe and why can they not make a 2.5" flange to mount which would be the beginning of the down pipe?

So this is what i want to have done.
2.5"Test pipe>2.5" down pipe>2.5" straight pipe> 2.5" inlet vibrant muffler with 3" dual outlets.
Why does it seem like this is so god dang hard. I know you need a cat for emissions and if the shop gets caught not using a cat they can be fined $10,000. Well is there an easy fix, maybe a high flow cat that can be welded in? I know my check engine light will be on but couldn't they just check the exhaust fumes?

To sum it up:
Do you need a flex pipe?
Where can you buy a 2.5" flange to bolt to the cat/Test pipe?
Why would a shop have trouble making the flange?
Is there a high flow CAT that can be welded in?
Would a 034 high flow cat be best even though i plan on running 2.5" pipe from the Cat back? (034 high flow cat is 3" pipe)

Please help me out?

[Seerlah]

The shop was telling you the truth. You should just pick up a 2.5" flex joint (should be able to pick it up at your local auto parts store, but make sure it is SS). A flex joint is necessary as to not make your exhaust system snap somewhere. With the movement of the motor and transmission, your exhaust system is not in a solid state. It moves, and needs the flex joint to keep things from breaking.
*
And the shop either didn't put too much thought into it, or was simply lazy about it. The flanges for our exhaust system, including turbo, is one found on maybe only a Porsche (forgot which model) and Audi/VW. Tell them to simply cut the flange off from your stock downpipe, and weld it onto your new downpipe for the flange. You should also pick up proper gaskets before you go to the shop. Are they going to make piping for you? If so, make sure it is mandrel bent. Also tell them to reuse all your exhaust hangers, including the one attached to the transmission. Tell them to cut them off of your stock system, and weld it onto your new one.

[Turbwhistle]

The shop was telling you the truth. You should just pick up a 2.5" flex joint (should be able to pick it up at your local auto parts store, but make sure it is SS). A flex joint is necessary as to not make your exhaust system snap somewhere. With the movement of the motor and transmission, your exhaust system is not in a solid state. It moves, and needs the flex joint to keep things from breaking.
*
And the shop either didn't put too much thought into it, or was simply lazy about it. The flanges for our exhaust system, including turbo, is one found on maybe only a Porsche (forgot which model) and Audi/VW. Tell them to simply cut the flange off from your stock downpipe, and weld it onto your new downpipe for the flange. You should also pick up proper gaskets before you go to the shop. Are they going to make piping for you? If so, make sure it is mandrel bent. Also tell them to reuse all your exhaust hangers, including the one attached to the transmission. Tell them to cut them off of your stock system, and weld it onto your new one.

I am going the end of this week to have my guy do it for me. He ordered me a new down pipe and will just do the rest of it him self. The other guy was pissing me off telling me it would be to loud and get me in trouble and telling my my car is not a race car and the flow doesn't matter for a 1.8t. I seriously was about to flip him off and leave. If you have a customer that knows what they want you do it, not tell them that its dumb. Any how, it should be done and sound good.

[SeekB00st]

Why not a 3" down pipe if your going to have a cat and a muffler. Also, I have a resonator and a muffler and it is way too loud. I previously had no resonator; it was intolerable.


Edit: I've also owned V8's with just mufflers and I have to say that the Audi straight piped was much more obnoxious.