if ur car is stock... don't worry about the gap... just look for the ones that are compatable w/ 91LS

and as far as size and part #....
standard NGK - BCPR5ES-11
iridium NGK - BCPR5EIX-11
V-Power NGK - BCPR5E-11
Platinum Bosch - FR8DPX
NGK Blue wires - HE56

just to give you a rough idea... NGK blues for the wires....