Audi 100 S4 Avant - Uprating help needed

[Tony Smith]

I've just purchased one of the above and wondered what was available in the way of uprated suspension. Not looking for anything fancy or rock hard - a little firmer and an inch or 2 lower would be ideal - any recomendations or suggestions?
Also has anybody fitted bigger rims - my tyres on my 16 " rims need replacing and I was some pondering some 9 spoke 18" RS lookalikes. How badly does this afffect the ride? Any help or advice much appreciated.
Lastly can anybody recommend a chip for the ECU - I thought there would be loads about but it seems if it can't be done through the serial port like on most new cars people no longer seem interested - or they just don't list them anymore! Anyone with an S4 or a 20v Quattro Turbo recommend anyone?
Cheers Tony