Hi ils,
Sorry to come in a bit late but I had this same dilemma and decided to go for a battery that was overspecc'd for my 996 to handle the shorter runs etc,l ie, less charging time and more starting. I went for the Odyssey PC680 (off the top of my head) it has around twice the cranking amps of the standard battery although is slightly heavier and slightly larger and I had to bodge up the mounting to get it in, all worth it though.
TP