I hate to break it to you buddy, but this forum only represents a small fraction of the Z owners in this country and around the world. You can't take a few examples from this forum and make any statistical judgements. This forum is statistically insignificant. Until you can show me some real numbers that can directly relate the number of failures compared to the number of UD pulley users compared to the number of stock pulley users and take into account the number of miles on each type you can't prove anything. If you go collect all that information for me I'll do the statistical analysis for you and we'll know the truth. My e-mail address is in my profile whenever you get it all gathered. Game over. Please try again.
Jonathan Howlett AIM-JRHZ32 1993 Ultra Red Twin Turbo 1990 Pearl Yellow Twin Turbo(Deceased)
OMG!!! Look what the ASP pulley did to my rod bearing!!