LOL-I missed it. The first time, My apologies. So you have a 6 speed a6 with a bit of an identity crisis. If it was a hitachi car you could flash any m-box file to it, but having a bosch maf means you must find files that have been altered to use the bosch maf. I'm not sure what your goals are here, but if you are looking for a tune to try make sure it says BOSCH MAF. Anything labeled stage 1 or stage 2 should be fine, but again, make sure it specifies it is for a bosch MAF.
If you are looking to create a tune (my recommendation), download the 8d0907551m bin, along with a matching XDF (for simplicity's sake I have attached them to this post). You're going to want to start by reading the s4 tuning wiki
http://s4wiki.com/wiki/TuningThe file I have attached already has the proper MAF tables for bosch, so no worries there (you can thank Jared AKA snowtrooper for that one). Make sure to find CLACINS in the xdf and set it to 0 to eliminate the can-timeout error code (p1650) that you will get flashing a bosch car with a hitachi file.
Now I know you're going to have more questions, but please refrain from asking them until you do some reading. If after you've read the s4 tuning wiki you still have questions, start a new thread.
ANYTIME YOU MAKE ANY CHANGES TO A FILE YOU MUST CORRECT THE CHECKSUMS. FAILING TO DO SO WILL RESULT IN YOUR CAR STARTING ONE TIME, THEN NEVER AGAIN (until you reflash the ecu with a file with correct checksums).
You can flash the file included and will gain approximately 20 hp over the stock a6 file. It is safe to flash until you are capable of creating your own file.
Welcome to nefmoto.