Adding a Kartboy lightweight crank pulley to the package.
This was one of my favourite mods, because throttle response was noticeably-sharper on install (felt the difference again as soon as I reverted to the stock crank pulley).
Easy to install.
The Kartboy does give a faint whine up to about 3,000rpm (sorta Supercharger-like), as it is designed without holes (unlike the Perrin and Grimmspeed) - on the flip side, it weighs the least (1.0lbs vs. 1.2lbs and 1.1lbs respectively for the Perrin and Grimmspeed).
The piece is in perfect condition, and will come with the original box (complete with a doodle of the serpentine belt on the box - a true collector's item!) and the unused Kartboy sticker (additional 5hp).
$90 for the pulley + filter, oil, coolant etc. (compares $120-$147.75 new, pre-tax)
It's a bit dusty on the inside
