I have a Underdrive pulley and a lightweight flywheel and am prying that nothing happens to my damb KA engine. I have had my UD pulley on my 240 for about 8 month now without any problems, but then like Mr Rose said you will never know till its to late. I had a UD pulley on my Z for 1.7 years without problems too, and the owner now 1 year later has had no problems. I would just stay away from the UD pulley cuz in all honesty is dosent do to much, in fact here is a Dyno of a UD pulley install that you all should be reading about in a up coming Sport Compact Car.
UD Pulley Install Dyno Results (Dyno is on Alex's s13 w/ AEM Prototype Intake and 5Zigen Exhaust)
