cooling system parts

[johnwoo]

hey guys im changing my fan clutch and my thermostat. so i went on pelican parts and saw that there are different choices for the two.  i have a 1991 318is which fan clutch do i need the "screw on type" or the other one. also i needed a thermostat there is two available.  which one do i get?  the 88 degree or the 92 degree.  let me know so i can place the order and can do work, thanks.