the Dinan software is focused on increasing power in the top of the rev range, where as Jim C. is more balanced throughout the rev range. i have the Jim C. chip in my 95 and after about 2800 rpm the engine just pulls like a motherfucker! The Beast also has teh Jim C. CAI and UUC exhuast but i really don't think the exhuast makes that much of a difference, just sounds nice.