This thread seems quite fitting as I've just bought and fitted some ta technix coilies on my s3. I got them off ebay for a mere £200 delivered from germany (they are listed as fitting a3 8l quattro I think). I've had experience with ta's on different cars before and wasn't disappointed this time either. Theres not a huge scope to go real low as it seems i'm only about 30-40mm and almost at the bottom of the adjustment at the fronts (although the helper springs are still in at the moment), and to go lower on the rears i'd have to take the adjuster platforms out but I'm not aiming to go real low so i'm not too bothered by that. At the moment mine sits very similar to how tufftys sits on the bilsteins shocks and apex springs. The ride is spot on, firm but not too harsh or unforgiving and a huge improvement on the worn standard stuff that it was on. Its ideal for me as my s3 is my daily driver and will only see some enthusiastic road use and not likely any track abuse.
I did go for rear camber arms too which I got from s3dave for about £185 delivered. So uprated adjustable suspension with a nice ride for less than 400 on an s3 is achievable contrary to what most will tell you. Also after doing my research I opted for leon cupra r top mount bushes and new top mount bearings too (about £60 more) but thats not essential. Its a lot of work to do yourself in a day (I did it all in 6 hours) and i'm lucky to have access to a ramp and tools so I guess thats a bonus as it cost me nothing to fit, but if tackled in a weekend with a friend its probably not so bad.
I think if you're on a budget its not as much of a gamble as you might think, you could be surprised at the end result for the relatively low cost spent. Yes some will question how long they last but the quality is at least adequate to last 3 years at a low or average yearly mileage i'd say.