Not sure what you mean by a stage 2 ecu..

If you get a proper rs turbo chip, then this will be able to see up to about 1.2-1.3 bar correctly.. having different boost levels is up to you really, it's pretty simple to have low/capsule boost (eg, 10-12 psi) and high boost (up to 23 psi) just by putting a switch on the amal valve..