Is the rear sway bar for the A4 with sports suspension the same as the one on the S4?

 

No.

The rear sway sizes are:

Standard -16mm
S-Line and Sport Suspension -18mm
S4 - 20mm
RS4 - 22mm

All are drop-in replacements for each other, meaning if you want to go up or down a size, there is no welding involved.
The bushings fit in the same brackets and you can order all through Audi at a relatively low price.
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i think hes talkin about the B5 rear sway and the sport and s4 are the same

 

I live exclusively in my B7 world and I frequently make this mistake.
My apologies if this info above is absolutely useless to you, JettaRedII.
And to pour salt in the wound, I don't know the answer to your original question.

 

Yah, Panda's right (per usual)

B5 S4 rear sway bar = B5 Sport Pkg rear sway bar (16mm each)

 

no its 19mm...

 

Thanks, guys. I should have been clearer. I am referring to the B5. Since the "sport-type" sway bar is under $100, I was hoping for a cheap upgrade. But since I have the sport suspension, I'm going to have to go with something aftermarket.

 

I really think the B5 Sport Pkg sway bar is 16mm...but whatever, I've been wrong before.

JettaRed, my Neuspeed bar set me back a little over $200 and I've got no complaints. Pretty easy install and a noticable difference.

 

I will get under the car and measure the bar’s diameter. $200 for the Neuspeed bar is pretty good. Where’d you get it for that price?