The ATI Super Damper Crank pulley is the way to go if your stock crank pulley has self destructed. While the Alta and Cravenspeed crank pulleys are GREAT options and will be light weight, and cost a lot less, they do not have the dampening capabilities of the ATI Super Damper when installed on your MINI Cooper S. The stock crank pulley on the MINI is notorious for failing and when it does it takes a few prisoners like the belt tensioner, the belt and some times other important and expensive. It's sort of a ticking time bomb and no one knows when it will blow up but they fail enough that ATI and others like Alta and Cravenspeed have stepped up to make lightweight aftermarket solutions that save nearly 5 pounds of unsprung weight. If you can't swing the cash for the ATI, the other crank pulleys on the market (that we also offer) are great alternatives. While these non dampened pulleys do not have the dampener integrated as the ATI does, it may lead to some extra wear on the crankshaft bearings. To date, I do not recall seeing a failed bearing that has been 100% linked to a non dampened crank pulley but it is likely that a non dampened pulley may produce extra wear over many thousands of miles. There is NO weight savings in going with the ATI over a replacement OEM crank pulley (but please don't waste your money on the OEM part...). This unit weighs in at 5lbs 7 ounces. Available in standard and oversized to suit your needs.

ATI Super Damper Crank Pulley for the MINI Cooper is 5.5” damper and works on the Mini Cooper standard and S engines. This new design is a direct replacement for the stock OEM Mini Cooper and Mini Cooper S damper from 2001 through 2006. The heart of this unit is the tried and true “damper within a damper” design that has put ATI ahead of the rest. The outer shell has been machined to allow OEM serpentine belt locations, and includes laser-etched timing marks.

Eliminates torsional crankshaft vibrations
Exceeds SFI 18.1 specs
Laser etched 360° timing marks
Black zinc chromate finished

copy and paste for instructions:
http://www.atiracing.com/instructions/917992-Mini-Cooper-Damper.pdf

Fits these MINI models:
Gen 1: 02-06 Hatchback Cooper S + 04-06 Convertible Cooper S (available in standard and oversize options)