So after reading around a lot on this forum and a particularly informative sticky post here:

http://www.audifreaks.com/forums/showthread.php?t=741

I replaced the stock non-sport shocks and springs on my 2001 A4 2.8 Q with the stock S4 shocks and stock A4 sport springs. I thought I share my experience for those looking to do similar.

First, I'll preface by saying that I was primarily interested in staying stock as I've had bad experiences in the past with aftermarket springs and shocks (not on Audis, but with Eibach and Tokico namely). Further, stock components tend to last longer and I'm not interested in updating the suspension every 50K miles. Additionally, I was primarily interested in reducing the fender gap, not in making the car a stiff hander. Improved handling will result from a lower ride height and if the springs and shocks made the car corner better, then great. But I really wanted to avoid the situation of loosing my fillings when driving over every pencil in the road (been there, done that, never again).

That said, I'll get to the details. I found that most people seem to do a straight swap of A4 to S4 (springs/shocks). This seems to be the result of a lot of low miles S4 components (S4'ers tend to upgrade suspension I suppose). However, I had read that S4 springs might actually lift the front of an A4 because the S4 is ~360 lbs heavier than the 1.8 A4 and ~150 lbs heavier than the 2.8 A4. So I set out to find A4 2.8Q stock sport suspension springs. Found them and used them instead of the S4 springs.

Some interesting things to note (this only applies to the B5 platform, of course):
1) The S4 and A4 2.8Q w/ sport suspension share the exact same part numbers for the rear springs and rear shocks. I confirmed this using vin numbers with my local Audi dealer.
2) The S4 front shock is not the same part as the A4 sport-suspension front shock (though both are red colored). That said, many "oem replacement" shops on line sell the same replacement part for S4 front shocks as the A4 sport suspension front shocks. So I felt comfortable that the valving was close enough to use the stock S4 shocks in front.
3) The S4 front spring is not the same (visibly) as the A4 sport suspension front spring.
4) The S4 front spring is nearly 3 inches shorter (uncompressed) than the stock A4 non-sport front spring (just interesting how much of a difference).
5) I read around and decided that the weight difference between the 1.8 and 2.8 was appreciable enough to avoid using any 1.8 suspension components.
6) Cost at the local shop was 3 hrs of labor (actually did it in 2.5 hrs).
7) Direct component swap, even reused the stock spring perches.

The results:
Ride height was reduced by about 1 to 1.5 in front and back. Handling is much improved, less boat-like, less roll around corners. Not something you'd take to the track, but nice. Ride quality seems unchanged, which is nice because this is a daily driver.

Hope this helps anyone looking to do the same.

 

The S4 spring should be much stiffer, though you probably made the right choice between the two since the S4 spring would be meant to handle the weight of the S4's v8.

 

Right, that's why I searched for the A4 sport springs. Also, the S4 only had a 2.7t (not a V8) on the B5 platform.

Thanks,
Matt

 

ah, my bad.

 

I just found this post and it makes me feel a lot better becuase I just purchased a set of s4 shocks and springs with 58,000 on them for $178 and I am putting them on my 2001 a4 2.8, replacing the non-sport shocks and springs that have just under 140,000 on them, so after reading this post I am really looking forward to the difference. Thanks

 

Heheh, I'm glad you found that. I read your post earlier about doing this and was going to link you to it but my phone battery died. I also put the same post on this forum but it wasn't stickies. I really liked the S4 setup on my car - as you said, really nice controlled ride.