So I have been in contact with my friend Ron at Modbargains and we are in the process of negotiating of prices for Cat backs and Downpipes from Billy Boat which is the exhaust that APR uses. Billy Boat is a high flow performance exhaust with a great sound and great gains.

***Update***

I have finally got the prices and the info with clips of sounds.

http://www.youtube.com/watch?v=AwqywQV43uI
and the B5 S4 is down below.

Retail Price B&B Audi exhaust B5,B6,B7,B8: $1050

5 People: 20% off, GB Price, $839.2,
10 People: 25% off, GB Price: $786.75,
15 People: 28% off, GB Price: $755.28,
20 People: 28% off, GB Price: $755.28

All prices do not include shipping: $65
2 week production time + 1 week for shipping to us after the orders are placed, then 1 week for us to ship out.

The exhausts are cat-back exhausts, so downpipes are essentially included already in the A4 original group buy, what is left is the test pipe, which I have calculated prices for:
The group buy pricing for the test pipes is the same scale.

Retail on B7/B8 Test pipes: $350

5 People: 20% off, GB Price, $280
10 People: 25% off, GB Price: $262.5
15 People: 28% off, GB Price: $252

Also, keep in mind, the B6/B7 S4 exhausts prices will be more than the A4 ones, due to higher MSRP and higher costs to us.

Shipping to Canada is $225 door to door.

If interested Email me your Name, Shipping Address, Part Number, and Phone Number where you can be contacted for any reason. Email is s4vagguy@gmail.com

If you have any questions comment or PM and I will be happy to answer them for you. This is a great opportunity to get a great exhaust at a great price!