4 ohm vs 8 ohm

You can use a mismatched speaker [ different ohms ] but the volume will be less & you could get some slight sound distortion.
Wouldn't be more ? A 4 ohm speaker on a 8 ohm amp should make more wattage, so if the components can handle the extra wattage/heat it may work or just burn our over time, doubt the OP gonna crank it so it might work. I'm not sure better with aftermarket amps.