I'm not technical and I don't work with cars, so forgive my stupidity, but I like the look of the MTM springs, so:
- who would you go to for installation?
- will it in any way affect warranty?
- I would think you need a full alignment afterwards, right?
- how much more rough is the ride afterwards? It's extremely smooth with stock springs, and I don't want it to annoy my wife and child in the back seat (only the child is in the back seat, not my wife)

 

Hi-
I did the MTM springs only and hated it. It bounced like a pogo stick on some surfaces...ok I'm being dramatic, but I did not like the ride and many others who did the springs only upgrade agree.
If Audi can PROVE that any aftermarket part caused failure of a stock system, they can deny your warranty. They can even deny it if they're not sure and don't want to pay for it, so it's really a gray area.
I recommend upgrading springs and shocks together both for ride comfort and for cost. If you decide later to upgrade shocks (like I did) you'll have to pay twice the install labor. It's the same process to install the springs. Most garages will charge you for about 4 - 8 hours depending on competency.
I am a BIG proponent of Bilstein sport yellows. Some people on the board will tell you they're underdamped, etc... All I can say is, ask them if they've ever driven the setup. Anyone who says they aren't right hasn't driven the setup...the end. The mechanic at my local Audi dealer dorve it and couldn't believe it. Handles like it's on rails. AND it's still comfortable. I really think it's the way to go.
Lastly, put the kid in front and the wife in the backseat! Makes for a much quieter trip.
For more info on the Bilsteins, call John at Autobahn Performance at 770-409-8288. Tell him it's the setup that Rick with the black S4 has. In fact, I believe he just got a set today.
Whatever you choose, good luck! And remember...looking is half the fun.

 

The ride is only minimally more firm over rough surfaces, but is MUCH improved as far as brake dive and wallowing after sudden steering inputs. You can order the springs from a number of dealers, Hoppen, Stratmosphere, etc, and you should have a local garage that you trust put them in and realign the car. If you have a good dealer( there must be one somewhere), they may do it. It will have no effect on the warranty. I think that your wife and child will feel that the ride is smoother with the new springs. It is an easy mod that many, including me, highly recommend.

'00 Silver S4
MTM Springs
MTM Stage 1 chip
UUC Drivetrain stabilizer
UUC 30% shift

 

You'll also notice much less bosy roll which I found to be annoying to me and passengers, especially when you get a little spirited. I had a local repair shop that specializes in Audis. They charged me $150. They are really good with Audis so it didn't take them very long.

 

i went over there to get an estimate
$1100 + install for bilstein/eibach.
its worth less than$ 800
and they wouldn't install anything bought elswhere.
unfriendly place all around too.

 

Al is right that the stock shocks do not provide the right amount (enough) dampening for the MTM springs. I used to say that I was going to add the shocks.

But after 4 months with the MTM springs only, my complaints have mostly vanished. I've done a couple of track days and the car handles great. There are a few road surfaces where a bit more dampening might be (would be) appreciated, but not many around Dallas.

I'd have to say that the spring only conversion is worlds better than stock. There's still some room for improvement. I'd actually prefer a bit more ground clearance and if my stock shocks go (or if WCOM ever recovers) I may get some stiffer shocks. But right now (and I drove 800 + miles last weekend, 200 of them at TWS on the track), I'm pretty happy with what I'm driving.

RR

 

been mentioned below. BUT, it introduced the wash board affect. Then hafter several months I got the Koni's installed. The total package is firmer and smoother than stock. One of the best mods i've done! If youu think you can live with the wash board affect just get the springs. I am just trying to save you the cost of two installs.

 

I actually looked at buying wheels from them about a year ago and they were really quite rude and unhelpful on the phone so I went into the shop to see what they were like. No much of a difference. Very arrogant salesperson that I talked to.

 

the stock (Sachs) shocks are OK, but the increased control (BTW: Get a 19mm rear anti-sway bar, too) will have you finding the limits of the OEM shox pretty quick.
on bumpy corner entry, on the brakes you get less dive (from springs) but tires chirp (from too fast rebound).
i am holding off getting replacement shocks 'till next spring in hopes that SOMEONE has fully adjustable (comp & rebound) units. [come-on Ohlins or GAB!!!]
OR... will upgrade to coil-overs.
wO