Also in regards to the Monza flap, wiring it open basically turns it into a Bombardone exhaust, so you lose some torque low down, the flap closed below 4krpm actually helps increase back pressure though the silencer, helping the turbo spool up more easily, above 4k rpm the flap opens and lets the exhaust gasses though the non silenced pipes, basically making it a racing exhaust where power at high rpm's are more important. The Monza is actually a very clever bit of design, the flap is actually there for a reason, not just so it sounds better. It basically gives you a street and a racing exhaust in one with the benefits of both.