[dvldoc]

You can use the MAF is you like, Alot of EVO guys do it and get the same effect. I'm pretty sure a 2002 WRX has a 2 bar sensor it actually reads up to only 17psi so a 3bar controller would be pretty far off.

On a 02 WRX the pin out should be just as shown in that diagram since it is a 02 schematic.

I really don't see the need to switch maps while driving, If you have a boost controller just turn down the boost and put the source of alcohol activation on a toggle.