Buy some standard ones from eBay and get them sprayed by your local bodyshop.
Do not paint them, they will only chip and flake eventually: ABS plastic is the only way
Black Audi Rings
Audi themselves, most obvious option.
AUDI TTS FOR SALE - £17k
I bought mine from Dupstopimports on Ebay, arrived within a week and were a perfect fit. These are in ABS plastic, so as Smoothie says they won't chip. x
Front grille badge -
AUDi A3 S3 A4 S4 FRONT EMBLEM BADGE - EURO MATTE BLACK | eBay
Rear badge -
AUDi A3 A4 A5 A6 REAR EMBLEM BADGE - EURO MATTE BLACK | eBay
MY10 S3 8P3 S-TRONIC, IMOLA YELLOW
SHARK PERFORMANCE STAGE 2 - GONE BUT NOT FORGOTTEN!