Originally Posted by WRX2LGT
It's only been one day, but I think I hate it actually. I'm not sure why anyone would want that noise specifically. It sounds like a belt broke and is flopping around the pulley, or the turbo has a bent fin and its ticking real hard. My tune has the computer saying 28mpg which I can't even begin to believe, but I don't want to mess with that at all. Seams like a lot of money to spend to get rid of a noise I don't like, I just can't figure out why anyone would actually want their car to do what mine does. I can hear my dad now..."why on earth would you do that on purpose?" Lol.
What does it actually do for the engine/turbo?
Because the wastegate is much bigger and independent of the turbo housing you can basically hold it closed longer to spool your turbo up faster and then slam it open and maintain stable boost. My understanding is that it doesn't give any more top end (unless you mess with the taper) but it increases spool time, boost stability and consequently more area under your power curves earlier on in the curve.
On top of that, if your iwg was having trouble holding boost to redline, this will give more of an ability to hold boost to redline (granted your turbo can support it) because of its larger diameter and more stable valve. The valve doesn't get pushed open by high speed high volume exhaust gasses as easily. That could also be contributed by the likelihood they come with stiffer springs.