I am using an alternator from a late 90's Kia Sportage, the original ones. Its 80-90 amp, bolts in place of the stock alt, and even new, much cheaper. I think its same as S5 for the plug, I just had to enlarge my pulley shaft a bit since the Spottage alt has a larger shaft, originally has a serpentine belt. I had an S4 alt before, so I grabbed the plug when I got my alt from the wreckers. It was an easy convert as kia wired the battery voltage wire on the plug straight to the large wire on the alternator. Just soldered on the new large battery cable pigtail, then ran the other wire to the charge light wire from the old S4 SLT plug.