I have a 2005 STI and it is totally standard except for a Cosworth Panel filter and Prodrive back box.

I thought that these cars boost from 4000 rpm, but mine is actually boosting from 3000 rpm, right up to around 6400 rpm. Although I'm not complaining, I thought it was out of the norm.

 

3000 is about right

 

Yes between 2700 to 3000 is normal on a stock UK car.

 

THey'll begin to build boost around that

But from memory my old standard 2005 STI didn't have an "real" boost until 4K

Get a decent exhaust system fitted and have it remapped man

Then you'll have "real" boost before 3K and it'll still be pushing strong at 6.5K