the quality from the 6x9s (if quality and 6x9s can be used in the same sentence), will only be as good as the quality of the amp...
it should be louder, but god knows why u got rid of the sub and kept the 6x9s, id have kept the sub and got rid of the 6x9s, better for sound quality...alot better! basically with the sub youre adding to create a 3-way component system