The 05 I worked on spiked to 21 and came down to 16 rather quickly.

 

My 05 (only Works Filter mod) will spike to 1.55 bar (22.5 psi). So I did a test on the open freeway at 2:00am, cuz I wanted to know if the 05 boost higher than the 03/04. I was in 5th gear at 35 mph and and the gas peddle floored. I would watch the boost gauge slowly go up. Once the turbo started to spool really fast at 3100 rpm the boost hit 1.45 bar (21 psi) and stayed there (it did bounce around between 1.44-1.46) until ~5600 rpm and the boost dropped to either 1.35 bar (19.5 psi) or 1.25 bar (18 psi). Had to slow down when I was aroun ~6000 rpm cuz I realize I was going way too fast on the freeway while trying to focus on rpm and boost. Next time I'm going to do it with someone in the car so I can keep my eye on the road. I was in the middle lane and was drifting into the other lane (there was still no cars on the road) that's why I'm not sure if it was 1.35 bar or 1.25 bar. When I have the time to do it again, I'll post my results.

 

My car is bone stock and I hit around 22 psi in 4th and 5th gears and then settle down to 20. The first 3 gears usually spike up to about 20-21...and then settle down to 19 or so. Again, thats with ZERO performance mods.