Gallo reference 3.1

I have a pair of old Gallows reference 3.1 and across the bottom subwoofer hookups I have a resistor that is 5 watt 15 ohm. So far so good, my amp is a pass labs int 250. I primarily listen to analog or vinyl if you prefer what my question is is that while my speakers sound good I'm wondering if changing the resistance will make any big difference or will it make it worse