Hey.. You already got an expert Evo guy over here..
..
Well the stock Evo boost is about 1.0 bar but then drops at a higher RPM somehow..
If you installed a boost controller on a stock turbo you can take it up to 1.2bar safely and by adding the boost controller you car will now hold the boost oh higher rpm. Ofcource this will increase the power of the car by alot and you will feel the difference.
For the most gain in electrical stuff for the Evo or any car.. you have to change the ECU. aka Chip.. I recomend Motec.. I tried Link and it sucks..