They are heavier than the factory batteries (although that is the lightest corner so extra weight could be an advantage there) and need to have the tray modified slightly to fit them. I'm not big into the miata scene, but I have yet to hear anyone in it say they'd rather have an optima than factory.
And Rich's replacement redtop is fine, or was on the way back and he hasn't mentioned having the same issue since. We originally thought there was something wrong with the charging system as well, but he didn't check. So although it's a good possibility, after hearing niX say he was on number 3 or 4 or 5 as well, I doubt it
