I may be being blind but I can't seem to find a for sale forum but I have a RaceChip GTS for sale originally cost £350 selling for £250. Its for a B7 A4 2.0 TFSI 220bhp. Takes it to 256bhp. All info in link below.
https://www.racechip.co.uk/shop/audi/a4-b7-2004-to-2008/2-0-tfsi-1984ccm-220hp-162kw-300nm.html
https://www.racechip.co.uk/shop/audi/a4-b7-2004-to-2008/2-0-tfsi-1984ccm-220hp-162kw-300nm.html