My car had piggyback pullies when I got it. From the day I left the lot it would misfire at high rpms and the dealer I got it from couldn't tell why. They sent it to another dealer and replaced the plugs, coilpacks and a ton of other stuff till they eventually figured out the crank pulley was losening itself. they tightened it several times and it kept getting lose. One day I ripped a nasty second and heard some clunking then saw the pulley rolling down the road. Turns out the bolt snapped off in the crank, leaving me needing a new shortblock on a car with less than 40k on it and a 14k loan on it.
The dealer said they wouldn't cover it but could put in a new oem shortblock for $3500, every lawyer I talked to wanted a $3000 retainer and I wasn't going to put up 3k to chance getting back 3500. I was S.O.L. so I decided to take out a second loan and build a motor since I owed more than the car was worth.Now I have 2 payments on the car and owe more than my buddy does on his termi.
I will never put an inferior part on my car (even tho they were on it when I got it). I know this is a worst case scenario nightmare but trust me is sucks to live it. Sorry to vent but I just wanted to share my horrible experience on the subject and hope it helps someone.