I have the 2011 Q7 with the supercharged 333 hp engine. Anyone have experience with modding this engine for more power? Water/Methanol Injection? Tuning? Anything else?

Go check out the B8 S4 forum, lots of info. APR & Stasis have ECU tune.

Also here is a spreadsheet of mods for the B8 S4 with lots of 3.0T engine stuff,

https://spreadsheets.google.com/ccc?key=0Ap0lshGutzFIdEJVSkg2VmdZUEVkeEt0VUI0VFVSb VE&hl=en#gid=4

Benchmarking speed improvements;

http://www.audizine.com/forum/showthread.php/391645-Official-1-4th-Quarter-Mile-Drag-Strip-Times.