Supression wire is essntially a resistor wire. The conductor is usually stuff that looks like string saturated with graphite powder. I don't know the specific resistance.
Metal core wire with a copper, bronze, aluminum, steel, or stainless steel conductor has very low resistance.
The usual approach with motorcycles is to use metal core wire and resistor plugs or plug caps to add some resistance in the coil secondary - this gives a longer duration spark which is generally a good thing.
Cars use the suppression wire to avoid RFI which causes buzzing and whirring in the car radio. It isn't to eliminate external interference really, just for the car's own radio.
If your bike radio has this buzzing noise proportionate to the engine RPM, then maybe suppression wire would be good. If not, then I would use metal core HT cable.
