ive had my yellow top in my z for a year and a half.. and no problems holding the charge on cold or hot days.. but from my experience if you do have a drainage problem your batteries will go.. ive had to replace 3 redtops on my supra for a bad cas.. but they were under warranty.. i highly recommend that if you do use a optima you have to make sure there is no leaks in the power system.. as the batteries themselfs are very expensive.(paid $160 cash for my yellow top)(120 for my red top)
