These are probably the biggest power gains that I've seen for the Turbo so far.

Kit 1: 3.6L
400KW/ 544HP / 6000 rpms
765Nm / 2000 - 4900 rpms

Kit 2: 3.6L
440KW / 598HP / 6550 rpms
795Nm / 2600 - 4700 rpms

Kit 3: 3.8L
455KW / 618HP / 6500 rpms
845Nm / 2500 - 4750 rpms

Kit 4: 3.8L
505KW / 687HP / 7000 rpms
900Nm / 4700 rpms

http://www.cargraphic.com/index.php?/s,6,7,18,2987,2988,3103