There is no right or wrong answer regarding remaps for the 1.8T - you just need to try them if possible and settle on the one which suits you best. This also extends to how the remap is fitted on the car - some serial tune, others solder chips! Try searching on this and other forums and you'll understand what i'm saying. There has been many (sometimes heated) discussions on remaps and tuners.
Revo remap wise, I deal with Wheelbase in Hersham, Surrey (
http://www.mega4.co.uk/) - they updated my code yesterday FOC and swapped my old SPS3 device for a new one. Simon, the guy who handles the Revo remapping has an S3 himself which is often used for development and is very helpful etc.
Brake wise, to be honest, you'll not see a drastic difference just replacing the discs and pads - the stock S3 caliper is only a single piston type and is not really up to the job of enthusiatic driving/braking. In fact if you use the wrong compound pad, then the increased friction will only lead to warping! Again, have a search on here - this one has been discussed many times.
M3 CSL - Silver Grey, a few options.
