One popular method of increasing performance on Supercharged cars is using a smaller pulley. The smaller gearing increases the boost provided by the supercharger.
Nearly every aftermarket tuner offers smaller pulleys. UPD suggests via its product pages that 80mm is safe without a tune and 77mm will require a tune on the 2003-2007 M113K. Please note the picture used in this post is of the UPD page. Please consider using their stuff which is of high quality.
