also don't know all the circumstances affecting your Optima battery, either, however strictly in regards to my own experiences with several Optima batteries so far I can attest to them being AMAZINGLY resilient and totally worth the money. One of my Optima yellow-tops had been drained down SEVERAL different times but still lasted 8 years. Sorry for your luck with it. What exactly is the difference in weight between an Optima yellow-top versus the light-weight battery? Is the light-weight battery engineered towards racing applications? Does the light-weight battery last longer than an Optima? Does the light-weight battery cost more than the Optima? Those are questions that would be on my Pros versus Cons list if I were to make a decision between the two.
Are you taking your car racing? Are you trying to get better fuel economy through less weight? Are you trying to achieve better weight distribution?