Mac performance underdrive pullies?

[The Green GT]

Anyone have them. Are they any good? Im bidding on a set on ebay right now.

 

[Roland69]

I think they have proved themselvs over and over again. someone on SN was sayin that they had a set of UPR pully's and the aluminum was wearing

 

[RIO5.0]

Had Mac's for years...not a prob....If their the Black Oxide ones, cheaper of the one's they make, they will slightly rust over time...