They are not using the VGT so far on the 04. 5 -05. The VGT has a collar on the exhaust housing which moves forward and back, depending on boost and rpm. On low RPM the collar moves in (or the vanes close in tighter) so it acts like a small turbo with quick spool up. On higher RPMs. the vanes open up,so it acts like a big turbo and the exhaust gasses can get out quickly, without choking the motor and causing high exhaust temps.
Garry