The chip is set to what it should be by apr, they dont do changes. The only othe ways would be standalone, or for just fuel a S-AFC. You can get a VAG and data log things such as MAf g/sec primary o2 sensor voltage which can convert to an a/F reading, n75 duty cylcle and alot lot more to but cant change anything there.

 

You could get the lemmiwinks program like jeff had. but you wouldnt want to start messing with that unless you actually knew what you were doing. And on a stock turbo, dont even waste your time.

 

i put a BOV on my brothers A4 three years ago and it is still running fine. although it could just be luck that nothing has happened. when i put it on it ran lean and would stall, so i customized it so it would divert some air back through and some to the atmosphere for a few weeks, then i vented it completely to atmosphere and it worked fine. since it wasn't one big change all at once, maybe it helped.