Seems that this one can.
Just got the demo of it and couldn't get it to show any boost, that could be because it's not connected to a vehicle (it should be in presentation mode though)..
Does anyone know where I might be doing something wrong?
edit - EcuTek makes the DeltaDash specifically for wrx's. It does not show boost, I have a feeling that I won't be able to get boost via OBD-II.
Boost is usually considered an "enhanced parameter". If this is a general obd2 scanner and not designed to read stuff specifically for your car it probably wont.
get delta dash from ecutek.com
Nano ITX / 512 MB / 60 GB / Panasonic slot load / M1-ATX / Bu303 / Sound blaster 24 / PPi amps / rockford sub
The Autotap link you reference is a list of Diagnostic Trouble Codes. It is not a list of real time available data (like boost pressure / map pressure).
The car's ECU may monitor the map sensor to see if an abnormal condition is being sensed. If so, it may trip a DTC with the issue. That is not to say that you can monitor the boost pressure with your device.
Map sensor is a fairly standard device to monitor as it is so important to vehicle driveability.