Sparky.... or Boomer...
IMHO, the dinky-toy-size MSP battery causes several things, including the "dimming lights when the a/c or defroster is on" phenomenon. I can't believe such current variance is good for, say, the ecu and other electronics...
Soon as I can I'm measuring the battery space (it's bigger than the cheapo stock battery is), heading to Wally Mart, and buying the biggest capacity battery they have - IIRC a year or two ago it was competitively-rated with other batteries in Consumer Reports. No, it doesn't have the status of, say, an Optima, but it's also less than half the cost, lasts about forever, and cranks like mad when cold (personal experience).
Unless someone can convince me otherwise, it's physical psace limitation and mountings (and weight) that "specifies" the battery - in other words, getting more cold cranking amps or a higher-rated battery isn't going to hurt anything - as long as it securely mounts in the battery compartment - the voltage is the same.
OK, well, as long as both terminals don't hit the hood at the same time when you close it... then just call me "Sparky"... or "Boomer"... (shocked) (blowup) (boom08)