1.Would it make a difference if you dont have the right amount of gauge wiring for an amps wattage? (I kinda know the answer)

2.what if you have a 4 gauge wiring kit that usually handles 400-1000w's(got the info from a site) and you have an amp that is just say 300-350w's...will it matter if you have too big of an gauge wiring kit?and will it affect/or harm the sound/amp anyway?