A part number would help a lot...not all the sensor use the same pinouts. you can swap 2.5 bar to 3.0 bar OEM ones with no issues, but without knowing what you're starting with and going to, it's hard to tell.
I did the OEM pinout here (posts 66 & 67)
http://forums.tdiclub.com/showthread.php?p=5365589#post5365589
From this and a spec sheet from whatever sensor you have, you should be able to figure it out.
You will likely encounter limp mode without a re-tune, but depending on the tuner, once it's running and you clear limp mode (scangauge or scan tool) it will make more boost - not necessarily more power - because the ECU has no idea that there's more air going in, or if it sees it, it will open the vanes and match fueling to the airflow. The ECU just thinks "hmm, the engine does not need as much boost today, ok..."
Modifications like this are at your own risk - have the gauges in place to monitor things until you know how the tune will react.
