It all depends on the turbo, and the tuning.
ALso the JDM head seem to be the best as far as flow.
You can get a drag turbo, midrange turbo whatever.
I hit 16 lb of boost around 3-4k and it goes up to 16.5 @ redline on stock turbo. With td04 I should be able to run 19lb all day long with quick spool time (close to stock) I sgould be puting down around 300 AWHP then, with the proper tunning (Custom map by COBB)
I wouldn't say that the power dies out,you just feel more af a hit when u launch it at full boost( obviously you are sending 230 hp to the wheels when berley rolling ) THe car grips very nicely, and I love when it rains now! DRIFTIN TIME