Here's a review from first time MotoringFile contributor Allan on his 2005 MCS after installing a 17% pulley.

I remember someone wrote a review of one the first '05 MCS, and he said it would be 'outrageous' to see someone put a 15% pulley on and '05 MCS with the new gearing (in every gear as we know from Autoweek's review). Well, here is a review of the17% pulley on my '05 MCS. I did it on Monday, at Helix Motorsports owned by Eric Savage. Eric has done about 235 installs of pulleys to date, so i figured my worry of reliability and warranty issues were at a minimum.

Knowing it was a trek for me to come from NYC, he made time for me after i originally cancelled my appointment because of work. At first, pulling out of the shop after the install, i was glad immediately, but even more of a difference was felt when l hit I-95N. Whoa! All I can tell you folks is that the upgrade is simply Sick!!! The scream, and i mean scream (esp., w/ my Pilo CAI), of the supercharger. Besides to getting 20 ft.lbs of torque and 15hp you have all you power- NOW! Another joy is being able, as JCW guys and girls know, stepping on it in 5th gear and feeling the car pull unbelievably is just priceless. I feel I have a new car now.

Around town if driven normally you would not know it was there, but, when you feel the need for spirited driving, it certainly shows up mightily. The pull begins hard from 3800 rpms on, and then it is rippingly steady till redline. The feeling is exhilarating folks. If you love torque, to feel your MCS pull like the Dickens, then this is the upgrade that you want. With the '05 gearing, increased hp and torque it so easy to light the tires in first & second gears if you are not judicious with the throttle and clutch, or have the DSC off. I can recommend this as the single most important fun factor performance upgrade an MCS owner can do. And if you want to hear the whir of that supercharger, a CAI.

The 17% is a little more aggressive on the low end than the 15%, while not having to worry about the issues of overdoing it with a 19%, and having to watch your redline duration. Btw, Eric puts a slightly smaller pulley belt on the 17% pulley so there is full strong contact on all the pulleys. This belt adds another $20 to the cost of the install bringing the total to $406. So if torque pull and grinning ear to ear is what you want to do when you drive you car on the road then this is it.