11.5%, 15%, 16% and 17% Reduction Supercharger Pulleys should all go on with a shortened belt without the real need to do anything else (except maybe change the plugs for safety).
As for which is the best, personally would go for them in the following order:
1) 15% or 17% Alta V2
2) 16% M7 (has all the advantages of the above except for the manner in which it attachs).
3) Wouldn't really consider any other as not aware of any other that have the features of the above 2.
Hardest part of the pulley upgrade is getting to and removing the original pulley in the first place safely. You need to ensure you have the right tools so you do it right first time. |