i got the rb25 turbo on my rb20 and its really noisy, sucking and hissing, probly the wastegate slightly open when not on full throttle,
When i put my foot down i cant hear the turbo hardly at all, just a big pshh when i take the foot off.
Try driving around with less throttle. or if that doesent work you could set it up shit like mine with no computer upgrade or boost controller.
Split dumps can sound cool too, i got a cheap and nasty one (JJR) and it has a stupid flange bit which doesent fit and has to be ground back so it makes a whizzing sound when the gasses go around it.
Im hoping to eliminate some of the noise, its ALL THE TIME and im over it.