BG 211 ISC is what Audi shops use. BG has great reputation and relationship with Audi VAG. Their chemists are head and shoulders above everyone else.
Use this with a an injection tool.
I used this on my wifes 2008 4.2 FSI. One application resolved all of the issues. Use this every 6 months to keep deposits from building up.
Use this with the OTC 7448A Fuel Injection Cleaner Canister. Available at Amazon. Nozzle and adapter required. If you need help fining an adapter or nozzle, contact me directly.