I'm running an 06 STi on Stage 1 right now and am hitting 16 PSI... (will be stage 2 this coming thursday as I ordered Invidia V3 Divorced Downpipe)
On a Cobb Stage 2 STi the numbers will generally range from 290AWHP/300+WTQ and about 310+AWHP/330AWTQ with a good protune.