i want to see what would be the better move to fight fantina in platinum with my luxio so would STAB neutral spark do more than dread plate boosted supper effective bite?
No. Stab adds a 1.5x bonus to attacks so it upps the 65P Spark to 97.5 (1.5x65=97.5) The Dread Plate adds a 1.2x bonus to dark type attacks and you get the 2x from it being super effective so the power of bite would be 144 (1.2x2x60=144)
So Bite with a Dread Plate and it being super effective would be alot better than STAB neutral Spark.