Well, I can understand your desire to keep your car as "factory" (wink-wink, nudge-nudge) as possible when taking it into the dealer for service. But I too am distrustful of a boost controler that does nothing to increase fuel while the volume of air is increased. Not good in the long run.
My solution to this quandry wasn't the cheapest, but it is effective. I bought an APR chip in a second ECU. So I have my stock ECU with it's stock fuel, boost and timing maps for service times. And I have my 1 bar ECU for the rest of the time. Not cheap (I spent $700 for that whole deal), but it works real well. I also have a VAG-COM to clear the battery disconected code that gets thrown everytime I change the ECU out, which isn't all that often.
Also, some cars had issues with that BCS controler. On some cars it just wouldn't work and caused all sort of problems for people. I say it's a gamble at best.
